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The Home Parallel Universe Test
Sam Sachdev writes "David Deutsch, a physcicist at Oxford, has designed a home test for parallel universes. Using a pin, a red laser pointer, a piece of paper, and a relatively dark room, he claims that the results from this experiment confirm the existence of parallel universes." Okay, so it may not really be proof of parallel universes, but it's a fun trick to try with a laser pointer nonetheless.
...about one and a half meters, or about five feet away for my metrically challenged Americans. At first, this humble journalist...
Man, what an ass. Sounds to me like a pompous buffon.
Oh yea, it was that one episode of McGyver.
I'll say it for you, 'laser pointers are cool!'
Anyways, there are plenty of ideas that come to mind that don't help this guys hypothesis. Phase, filtering, and the plethora of other particles in the room come to mind.
Isn't this the same old double-slit experiment, just slightly modified? Perhaps this is new to some people, but anyone who's had the slightest interest in quantum mechanics or parallel universes should have heard of this by now.
---- El diablo esta en mis pantalones! Mire, mire!
I thought the double slit experiment was intended to show that light behaved as both a particle and a wave.
"Come on, let's go drink till we can't feel feelings anymore."
I read all that (yes I'm new here) and it didnt explain where those 2 other shadows went. Anyone care to explain ?
i tried it and the laser turned 90 degress midair
does that mean i have a perpendicular universe?
Detection of tachyons now possible via the usage of duck tape, scissors, a wooden spoon, and a very unhappy hamster.
Dude, I really want to see this parallel universe... doesn't he even have pictures?
A fool throws a stone into a well and a thousand sages can not remove it.
I did something similar for an 8th grade science fair where I had 3 polarized lenses set in 3 different slots in a tube. When one lense is turned to a angle of another lense no light comes through the tube. However, if you then put a third lense in between the two other lenses and turn it light will come through the tube again. It was supposed to show how light has properties of both particles and waves. Beyond that it became Buckaroo Bonzai quantum physics stuff.
Couldn't it just be out of phase like those noise-cancelling headphones?
-I am an elective eunuch.
http://freecache.org/http://www.allsci.com/paralle l.html
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A Home Test for Parallel Universes
by Sam Sachdev
March, 2004
When you think of a parallel universe, do you think of a universe, or a world, similar to ours but different in some fundamental quality. Bill Clinton, for instance, is a happily celibate priest. Or George W. Bush delights his fellow Mensa members, at parties, with his verbal games. Or, perhaps, you only have a science-fiction quality vagueness to what you think of a parallel universe: pointed ears, warp-drive through worm holes, and form fitting Lycra body suits on a thin, well-groomed crew. A parallel universe, it may surprise you to learn, is actually detectable in your own home, office, or almost anywhere indoors. All that's required is a red laser pointer, a pin, and a piece of paper.
With the aid of David Deutsch, a physicist at Oxford University and his excellent book "The Fabric of Reality", the experiment, in a step-by-step process, is going to be set-up and, then, it's going to be explained why this magic-like result from this experiment is indeed proof of a parallel universe.
First, a red laser pointer is needed. I found one at Radio Shack for $19, not including the triple A batteries that were needed. The red color of the laser pointer is important. The red light, unlike the white light of a flashlight, which is a composite of many colors, doesn't fray as white light does. The red light, specifically, of the laser pointer casts more specific shadows - which is what this experiment does. A flashlight, according to Deutsch, can probably be substituted. A filter, however, is going to have to be placed over the white beam. The filter, can only be red colored glass; paper or any other filter won't work.
Next, a relatively large, dark room is needed. The room should be large enough to set up the laser pointer on, say, a table, and have it cast its light on a wall about one and a half meters, or about five feet away for my metrically challenged Americans. At first, this humble journalist tried to do the experiment, during the bright light of a Washington, DC winter day, in a walk-in closet and a bathroom. Both weren't large enough. My dining room, when the sun had set, was.
David Deutsch recommends a room that's almost totally dark. I found, however, that this was too dark. The experiment requires enough light to manipulate the laser pointer. What I did was have a light on in another room, which provided enough light to see what I was doing but dark enough to see the shadow cast by the laser pointer.
The experiment is best done with done with two people, with one handling the laser pointer and the other observing the pattern on the wall. The positions can then be switched. Be careful, however, not to shine the laser light into the other's eyes.
If you don't have two people, this is what I recommend. Fold a piece of paper in half and place it on the table, so that one half is perpendicular to the table. Then, using a book, or anything to set the laser pointer on, aim the pointer at the paper. Mark where the red light hits the paper. Using a pin (and only a pin, not a tack, the holes have to be as small as possible) punch two holes, on the mark, as close to each other as you can. Then, aiming the laser pointer at the two small holes, a shadow of five slits should be cast on the wall. That is, there's going to be one large red dot cast on the wall. In the dot, there should be five distinct shadows cast by the two holes. If this doesn't work, the most common problem I found was that there wasn't enough distance between the paper and the wall. If possible, increase the distance. David Deutsch recommends about five meters, or fifteen feet, but I found about five feet, or a meter and a half, was enough to observe the pattern.
Why, you may be wondering, are there five slits of shadows when there are only two holes? That's because light, as you
Why not perpendicular, or skew? I think that differently oriented manifolds are being discriminated against!
When things get complex, multiply by the complex conjugate.
IANAP, but doesn't this simply demonstrate wave interference? as in:
u ng .htm
http://www.cavendishscience.org/phys/tyoung/tyo
Is the point not that such universes exist
"next to each other" with no connection what so ever. If you live inside a parallel universe you can't detect other universes outside.
Sounds like the Dark Sucker Theory...
I'm no physicist, but the article talks about photons and their properties, then mid sentence and afterwards begins referring to them as protons and THEIR properties, then goes on with a description of some photon/proton hybrid logic
Is this a joke article?
Hawking describes this type of thing in A Brief History of Time. This is NOT proof of a paralell universe, it's proof that light travels as a wave as well as a particle.
LK
"Hi. This is my friend, Jack Shit, and you don't know him." - Lord Kano
This kind of pseudoscientific articles are one of the worst things on the internet!
This is a classic optics experiment to show that light has wave properties, and it has NOTHING to do with parallell universes. It is all explained here:
diffraction
And if you want to show any quantum mechanical effects you need to make sure that only one photon leaves the laser at any given moment, and that is not happening here.
Sam Sachdev writes "David Deutsch, a physcicist at Oxford, has designed a home test for red laser pointers. Using a pin, a parallel universe, a piece of paper, and a relatively dark room, he claims that the results from this experiment confirm the existence of laser pointers." Okay, so it may not really be proof of laser pointers, but it's a fun trick to try with a parallel universe nonetheless.
Old experiment, old result, new conclusion. Bad science. Poor writing.
This experiment sounds very much like an experiment used to show that light not only acts like a particle but also as a wave. I have not performed this experiment myself but it sounds as if the patterns produced on the wall are produced by the light being bent as it passes through the slits and displaying a wave pattern. Much like the way water would behave if a wave passed through a narrow opening into a broader area - it would spread out. Perhaps what is happening in this experiment is simply two of the waves cancelling each other out completely. That would explain why two of the patterns disappear.
But of course, I'm not a physicist nor have I ever studied particle theory or quantum mechanics. So maybe I'm off-base.
You have understood nothing. The phenomenon is real and one of the strangest and most spooky things in physics. It shows that it it possible to get a particle (in this case a photon) to interfere with itself.
The only question is how you interpret it. The first interpretation, created by Einstein, Bohr and other dignitaries of the time, was the "Copenhagen Interpretation" which requires an "observer".
The "Many-worlds interpretation", first thought of in the late fifties gets rid of the need for a mystical observer by introducing parallell universes, where entangled particles can still interfere with each other.
This interpretation is championed by many of the leading physicists. For example Deutsch and Murray Gell-Mann.
I believe Feynman has a strange third interpretation involving particles travelling backwards in time, that cancel out the waves of forward travelling particles at specific points in space-time.
Opinions stated are mine and do not reflect those of the Illuminati
When I tried this experement I ended up with a 3D holographic image of the words "There is no alternet universe"
and a few moments later someone whispered
"If you try that again we'll eat your soul"
So there is no alternet universe...
Ok mister spooky voice you can stop making my walls bleed. And could you remove the chains from the door? I will NOT be entering that hole in the wall ok?
I don't actually exist.
If this test was done by an overclocker, you wouldn't have any stinkin' batteries - you'd have a flux capacitor powering it.
These guys are amateurs.
had a couple mod points but it wouldn't let me mod the article down... :(
In the article, "shadow photons" become "shadow protons" between one sentence and the next. Perhaps that's advanced physics, but I suspect the writer got something confused. Can anyone straighten it out?
Sheesh, evil *and* a jerk. -- Jade
Why this is suspicious: It seems a little strange that only _one_ source is cited throughout the article, david deutsch. False information by third paragraph: First, a red laser pointer is needed. I found one at Radio Shack for $19, not including the triple A batteries that were needed. The red color of the laser pointer is important. The red light, unlike the white light of a flashlight, which is a composite of many colors, doesn't fray as white light does. The red light, specifically, of the laser pointer casts more specific shadows - which is what this experiment does. A flashlight, according to Deutsch, can probably be substituted. A filter, however, is going to have to be placed over the white beam. The filter, can only be red colored glass; paper or any other filter won't work. Yes, a laser is needed, but not because it is red, in fact any color laser should work, red is just the cheapest. The reason for a laser is that it provides coherent light, that is all the light that is emited is in phase. This is necsessary for the interference. Sachdev tries to explain the interference soley in terms of particles, when in fact the light is behaving as a wave. He is entirely neglecting the wave-particle dualty, and resorts to parrallel universes to explain it in terms of particles.
...you can see ladies taking their clothes off.
Sheesh, evil *and* a jerk. -- Jade
Shadow Protons?
\\snort\\
As, from what I know, protons are mearly balls/waveforms of energy, which activate receptors in our eyes, showing us the light, so to speak. So if a so called shadow proton hit one of these receptors, what would we see? Darkness? Gotta love this home-brew science.
Sig
Dear CowboyNeal, I strongly object to your writing "Okay, so it may not really be proof of parallel universes,.."
You make it sound like there is a chance that there will be a proof sometime for something in physics. Per definition, it can never be a proof for anything in phyciscs. There can only be modells and experiments that contradicts the modell or that "confirms" the modell.
Evolution of Language Through The Ages: 6000 BC : ungh, grrf, booga 2000 AD : grep, awk, sed
Second of all, he credits David Deutsch with an idea that most certainly is not his. Both the notion of wave functions (what this article is talking about) and the idea that this somehow relates to parallel universes are older than I am.
This is not a revolutionary idea, and it is not really a controversial one either, as the author of the article seems to indicate. This is just one explanation of a curious quantum mechanical effect. There are other explanations, and they all describe what happens quite accurately. They may each have their own proponents, but really none of them is wrong--they are just different interpretations.
I generally do not like griping, but this write up is positively abysmal. It is no offense to David Deutsch--I am sure he is a quite competent individual. But I do not think the author of this paper actually read his book. It sounds too much like the BS I would string together from reading the first few chapters and the epilogue when I had a book assignment in schoool.
Go here for a decent, intuitive, layman's introduction to various quantum mechanical oddities.
When things get complex, multiply by the complex conjugate.
Junk science is everywhere. This, though, is the first time I've ever seen something along the lines of string theory's extra dimensions being "proven" by interference of waves.
Is there any way to mod down the fool who wrote the article?
I tried this, and everything changed! I'm fat! My beautiful wife is gone! My beautiful aircar is gone! All of my stuff is crammed into this stupid apartment!
I can't even find a link to the nearest spaceport on Google!
How do I get back home?!?!?!?!?!
What a bunch of unintelligible nonsense. I'm sure David Deutsch would explain this differently. Whatever he told the author of the article has been lost somewhere. Probably in the vacuous head of the author. He doesn't mention how light behaves as particles AND waves at the same time. He talks about "shadows" going dark. In fact, when I was done reading the article I wasn't sure what he meant by his use of the word "shadow" at all. The writer did a terrible job of explaining what's going on in this experiment and what it's supposed to represent.
Time, I guess, to DTFE.
My parallel self tried it and said that it didn't work.
___
It's the end of my comment as I know it and I feel fine.
I tried the experiment myself, and Dr. Deutsch is right! Through the holes, I saw images from many parallel universes, worlds in which Columbus discovered Europe, Lincoln shot President Booth, and Germany and Japan saved the world from Nazi America and Fascist Britain in WWII. (However, Michael Jackson is a disfigured weirdo pervert in every parallel world. Must be a fundamental physical law, like the speed of light.)
One example of home parallel universe test
This is a version of the Many worlds interpretation of quantum mechanics first expressed Hugh Everett in 1957.
The article is very flawed, but don't let that reflect on David Deutsch who is very smart unlike the article.
The "parallel universe" part comes in to explain why it still works if you fire single photons, but since you can't fire single photons (or easily check the results if you could), this isn't really a "home test" of any use.
The fact that single photons can make a diffraction pattern, seemingly interfering with themselves, is a truly weird feature of quantum mechanics (but then, I repeat myself -- quantum mechanics is always truly weird!). And one of the explanations proposed is that light in parallel universes is somehow causing the interference with the single photons in this universe.
Another explanation is that light sometimes acts as a particle, and sometimes as a wave, and when you detect a single photon coming through a slit, you are forcing that photon to act like a particle, and it will not throw a diffraction pattern; but if there is no measurement to decide which slit the photon passed through, the light can act as a wave instead of a particle, and can have an interference pattern.
http://www.starlight-pub.com/UnitNatureofMatter/P
This page lists various explanations of why the single-photon two-slit experiment behaves as it does. One of the explanations is the parallel-universes one.
http://members.aol.com/jmtsgibbs/TwoSlit.htm
Here's just the part with the "Many-Worlds Interpretation":
steveha
lf(1): it's like ls(1) but sorts filenames by extension, tersely
Well, how do you know if you live in such a "multiverse"? The answer was proposed by Max Tegmark just a few years back:
Take a gun, put it to your head, and pull the trigger. Repeat several times. If the multiverse model is correct, then your "self" will continue to exist only in those universes where the gun does not fire. So if you try and pull it a bunch of times and nothing happens, you must be one of the many parallel yous who happens to live in a universe where, in spite of probability, the gun did not fire.
Of course, I would not recommend trying it. If the MWI is correct, well, then in another universe you already have tried.
When things get complex, multiply by the complex conjugate.
I think that if you take to the time, and scroll down to about the 15 paragraph you can find an excellent description of what's taking place. Essentially we've all been educated wrong, and http://www.timecube.com/ can be the best way to start all over again.
You have understood nothing. The phenomenon is real and one of the strangest and most spooky things in physics. It shows that it it possible to get a particle (in this case a photon) to interfere with itself.
and so, out of guilt and self-loathing, it hides itself from the observer?
That should pretty much sum up the legitimacy of the article.
This is a very old experiment, and a well-known phenomenon. It was even one of the answers on slashdot's poll for favourite physics experiment (and my personal favourite).
Even the idea that it is proof of parallel universes is not original. Michael Crichton made that claim in his book Timeline. It's an excellent book (despite the horrible movie loosely based on it), but it is fiction.
Jason
ProfQuotes
1. The universe here Bill Gates' computer science tutor at university said "That's a crap piece of code, Bill. I'm putting you in the law degree class."
2. The universe where Jon Bon Jovi hijacked Stevie Ray Vaughan's plane and got killed instead.
3. The universe where Darl McBride wasn't dropped on his head as an infant.
4. The universe where whenever you post something off-topic to Slashdot you get disconnected and...
[CLICK]
Gentoo Linux - another day, another USE flag.
Hey honey, come back to my place and we can make paralell universes together.
And if you thought that was boring you obviously havn't read my Journal ;-)
Keyword- freelance
I do not, I repeat, I do NOT understand why this guy is getting funding at all to do this sort of research. My goodness, I'm in control theory and it is nearly impossible to get funding despite its immediate engineering applications! There is something seriously wrong with the world. I'm in a badass parallel universe.
I think that this physicist must be wrong. It is obvious that that this experiment only shows photons acting as both particle and waves. See my high school physics book proves me right. They should give me a Phd right now just for reading it. In 10 years when this theory is proved to be at least probably wrong, I will say I told everyone so.
I would like to point to a former post I made which mentionned this earlier, about the two-slit experiment:
"An interesting theory trying to explain this seemingly inexplicable result, is by taking the hypothetical possibility that the bands are created by photons that exceed the speed of light. Only when they revert to another (visible) quantummechanical state (by hitting the wall, for instance) do they become noticable.
This is not impossible, because, contrary to what most ppl think, lightspeed is in fact an average; within one beam, there can be photons that are moving slightly slower, and photons that move slightly faster then the speed of light.
This, however, leads to the conclusion that those particular photons come from - at least potentially - another time or space. So, the film 'paycheck' might not be complete bullocks after all (though it's doubtfull we are ever going to be able to create a usefull 'time-viewing' tool out of it).
Then again, never say never, as Bill Gates with his '640K is enough for everyone' can vow.
The theory about another 'space', in contrast, leads us to the possibility that those photons actually come from parallell universes. It seems SF, but it are, in effect, valid scientific hypotheses which deserve further investigation.
After all, apart from these theories, there *is* no explication for the result of that experiment."
While I have had a lot of criticism for the 'faster then light' therory (though I didn't invent it, and it *was* proposed as a hypothesis), the 'parallel universes' hypothesis is a bit more well known, it would seem.
--- "To pee or not to pee, that is the question." ---
This is crap.
Photons or protons?
Shadows being blocked?
Completely undecipherable.
It's the reporter's fault not the Author
,say, 50%. (prior to the measurement)
This happens a lot when you look at popular science.
The reporter read the back cover of the book, and the introduction, then he made a lot of stuff up to fill the blanks
The Two slit experiment(look it up if you are interested) is rather old. and i guess would fit into the introduction of the book.
after you've eqplained about the quntum nature of photons, there rises a question of , so what does it mean to be in a quantum state with a probability of
now, one explanation, is the Many World explanation (the Copenhagen... IIRC)
I feel sorry for the author of the book who is probably tearing his hair out in frustration.
-- Avishalom is usually vish
Someone's been looking at movies ala "The One" a tad to much...
Again, as has been said before, this is the worst piece of pseudo science I have even seen. Shadow photons? We would have detected them by now in our particle acclerators (especially as you can "detect" them this way with a home laser. The Standard Model so far works just fine (much to many physicists' regrets) and has no shadow photons in it. No offense to Dr. Deutsch but also its a little outside his field as he's an atomic/laser physicist. I've never heard the particle or theory guys talking about "shadow photons" and I would know as I'm a particle physics DPhil student at Oxford.
... for instance, is a happily celibate priest? Nahhhhh... This can't be real! Scrap the parallel universe theory!
Free Firefox news reader.
Shining a laser-pointer, through the jaws of a pair of nailclippers, onto a screen, you can get a Single slit diffraction pattern.
Firstly, as others have pointed out, this is essencially the double slit experiment. In this case, because he's just using laser light, this simply demonstrates the interference of waves.
More interesting results come from when you pass through single electrons or photons one at a time, and they show the same behaviour, but this experiment does not demonstrate this. Nor is the only explanation for this to assume parallel universes. The so-called "Many Worlds" theory.
In fact, according to this, the Many Worlds theory has been invalidated by a recent experiment.
So not only does this laser-pen experiment not prove the existence of parallel universes, but the Many Worlds explanation of the phenomenon has been potentially been already disproven.
It always cracks me up when someone references wikipedia as if it's an authoritative source.
I've known the neatness about photons being waves and particles, depending on the circumstances...
What I've never even thought to ask is why? I don't know if I'm asking quite the right question, here, but...
I suppose what I'm asking is when is it one or the other?
Assume I was drunk when I posted this.
I did the experiment and have confirmed the results! Parallel universes exist, and I think David Deutsch is a genius! I have registered www.daviddeutsch.com and I will be building a shrine site to David Deutsch this week, so check back often! If there are people in this parallel universe, we need to contact them!!! Does anyone know if the people you talk to on an Ouija board are from this parallel universe?
Feyman's idea is to treat antiparticles as particles travelling back in time. it's mostly just a trick to make calculations easier (this of course means it must be a valid interpretation).
"David Deutsch, using an experimentally confirmed prediction from quantum theory, believes that what's causing the interference are shadow photons." Oh yeah, that's what experiments do, alright. They confirm theories. Good grief. Theoretical physicists need to be beaten about the head and shoulders with slide rules by engineers, probably on a monthly basis.
GWB ... for instance, is intelligent? Nahhhhh... This can't be real! Scrap the parallel universe theory!
This is just a version of the classic double-slit experiment of quantum mechanics.
Deutch believes in multiple universes. He uses this belief to explain the results, but typically for Deutch he says the results prove his belief, which is nonsense. There are many other explanations and one of the strangest aspects of quantum mechanics is that there is probably no way to say which explanation is right. Some of the other explanations are equally weird: the Copenhagen interpretation says that particles only 'collapse' into definite positions when something looks at them. The Transactional interpretation (my favourite) explains the results by assuming that particles are continually interacting back and forth in time. Other ideas include the suggestion that quantum states collapse into what we see when things get large enough for gravity to be significant (to put it simply).
Of course, the most sensible interpretation is to take the scientifically humble attitude and say that we don't fully understand what is going on and can't explain it, rather than to arrogantly assume all results 'prove' your personal metaphysical beliefs.
(how's that for a quantum theory like answer)
What the attempt is in this area is to come up with experiments where the results are not predictable by wave theory. Either the results appear to show the presense of ghost photons or the interference patterns are not as expected (with interesting conjectures of how that could arise).
in a place you dont know anything about?
I'm amazed they even bothered with learning English, but I guess the watched ST and figured it was a language that would apply almost everywhere
Bush is a mensa member?
THIS i Gotta See.
Parallel Universe ! Here i come !!!
Maybe he's understood nothing because the bozo who wrote that article explained nothing. The phenomenon was poorly described, and the guy didn't waste any time explaining that waves act like this before diving in to this entirely unscientific many worlds interpretation nonsense.
Just because you already knew this stuff doesn't mean that someone who didn't come to your level of understanding of it after reading that article has "understood nothing".
There isn't really anything mystical with the "observer", after all, it's only a way of talking about an interfering particle, isn't it?
As I understood it, superposition of states is the way it's ususally seen (and described as), but some physicists want to keep things more deterministic, and introduce parallel (deterministic) universes instead of a single indeterministic one.
xkcd is not in the sudoers file. This incident will be reported.
Not to be derogatory in anyway but We had to use this experiment to find the wavelength of a laser in a Science Olympiad competition in High School. Of course they handed me a metal string a piece of paper with a hole in it (to mount the string on and project the laser through) and a nother paper to difuse and measure the wave length of the laser on. Needless to say I had a much less strong notion of physics back then but the thought had crossed my mind that the photons would interact with themselves but I never Chalked it up to Many Worlds theory. When I see the effect of water rippling or sound bouncing I can't come to the same conclusion, and knowingly enough photons, or light, act very similar if not exactly like every other waveform in nature.
Well, no. If you use such a weak light source that only single photons are emitted at a time, over time these photons will build up into an identical diffraction pattern. Weirdness.
My interpretation, the "Many-Copenhagen" interpretation, states that all the parallel universes are carbon-copies of Copenhagen.
Big apple, new Yorik, undig it, something's unrotting in Edenmark.
One red laser pointer: $19 1 pin: $.99 1 sheet of paper: $.05 Proof of an infinite number of parallel universes where you're STILL not getting laid: Priceless
Ok, this proves quantum theory. Saying that parralel universes therefore follow is either gross oversimplification or just forcing your metaphysical opinions of a physical theory on others. And yes, Young's double slits, old news. Also, this doesn't show that light is a wave. This demonstrates that a photon can be placed in superposition. This experiment has also been done with electron beams, whole atoms, and (IIRC) C60 (buckminsterfullerene), and they make interference paterns. Now atoms are definitely particles.
# cat
Damn, my RAM is full of llamas.
"Scientist" Discovers Light Interference Patterns - Claims Miracle
David Deutsch, physicist at Oxford University, today discovered that when directional monochromatic coherent beams of light, amplified by stimulated emission of radiation, are directed through pinholes and caused to overlap, a "mysterious shadowy nonsense pattern" is observed. He commented that as one adds more pinholes, the shadowy nonsense becomes even more mystical.
His highschool Physics tutor, known to his students Mr. Bradshaw and to his friends and family as Mr. Bradshaw, commented: "Dave was always into physics and all that stuff. He thought it was ace, but the school couldn't afford as much as a light bulb in them days and he was off sick with rubella on the day of our school trip to CERN, and so never got into those laser thingumyjiggies". Until now; The UK government has recently granted Deutsch a $17 million research budget for the further investigation of things people are already aware of, a sum that is belittled by the sales figures for his book "Amazing things to do and then fail to understand", which has shot to position 1,237 in best seller listings and is heralded as "bewilderingly unfounded and lacklustre".
Photons somehow became protons, and then the protons had atoms in them....
Adds to that whole pseudoscience air about it.
The experiment described is actually a "four slit" Young experiment. It's a classical exercise to show that when you go from two to three slits you have an irregular pattern, and as you increase the number of slits only the "main" peaks survive ;
(nice geometric series of complex exponentials in the calculation) ; this is the principle of the diffraction grating used nowadays instead of prisms in monochromators and spectrometers. What happens here is that when going from two to four slits the diffraction and the short coherence length of a laser pointer (maybe 1mm) make that only three peaks are visible. With a better laser (say a 30 cm long He/Ne) you would see maybe 12 peaks. And if you use a photodetector on the screen, you detect the two missing peaks, which your eye cannot !
Google passes Turing test : see my journal
I think the title is quite misleading,
and I still don't get why this whole
story couldn't be about a desctructive
interference as in with sound waves.
"With the introduction of the two new holes,
a destructive inteference appears in 3 of the shadows"
Or some other wave-theory application maybe?
The Transactional interpretation of John Cramer has only one rule (the transaction), no Unicorns and no Multiple Worlds.
Occams razor?
Of course, to say that there are no collapses in the Many Worlds interpretation is nonsense: After all, each parallel self in each universe only sees one outcome, so for each self there has, in effect, been a collapse. Its only from the point of view of a hypothetical (and impossible) observer of the entire multiverse that there is no collapse. In a sense, the Many Worlds interpretation has a phenomenal number of collapses as each new parallel self sees a distinct outcome. That is not an Occam-compatible explanation of things.
That one has baffled linguists for centuries...
and it is said that quite a few older, bitter linguists like to drown their sorrows in "whisghian sohdahhs"...
"Empathise with stupidity, and you're halfway to thinking like an idiot." - Iain M. Banks
I've read the material, and cannot see anything that proves that a photon can interfere with it's self.
I believe the double slit, single photon effect to be an artefact caused by the photon interacting with something we can't see (say space) and causing a drag that then interferes with the photon.
Lets say I(the photon) walk down a slope(momentum), as I go I bump into all kinds of things(if I didn't then I wouldn't really exist).
Why can't some of the things take a different path down the slope and interfere with me later.
A bit like the ball and peg experiment but with lots of invisible balls to get knocked along the way.
It sounds far easier than untold universes and wave function collapse.
Secondly, if a single photon creates the effect, what to say that the effect isn't the accumulation of a lot of photons creating there own little effect, that also seems more probable.
The experement may however show that light can be changed by gravity.
thank God the internet isn't a human right.
False. I have a very sligh interest in parallel universes, but I had not heard of this until now.
This is nothing new, even in mainstream press. It was even published in Dilbert Future which came out about 5 years ago!
--
This sig is inoffensive.
this is what is causing the interference, "[W]hen a photon passes through one of four slits, some shadow photons pass through the other three slits." The shadow protons, then, are blocking the tangible protons, causing only three shadow slits.
... so what do I know? Maybe it does make sense ... but Parallel Universes? I don't know .. sounds like he's reaching for an answer to explain the unobservable. Given time, this ?theory? of his will be proven wrong. You know how it is... the world is flat, the sound barrier can never be broken, 640k is enough for anything, etc...
These shadow protons form a parallel universe.
I'm reminded of a Star Trek: TNG episode where Data went down to some planet to collect radioactive rocks. Somehow he short circuited (or whatever - I'm not much of a Star Trek fan) and "forgot" who he was and ended up in this small village full of people that were several centuries behind the human race.
While in this village, Data sat at a table listening to a teacher explain to her student what the various forms of matter were. In one of her explanations (and you star trek geeks will have to forgive me if I'm getting the details wrong here) but she said that fire was "inside" of wood and that it could only be released by heating it up... Data interjected and said that he felt like her conclusion had to be wrong for such and such reason. And throughout the episode he demonstrates a couple of other (obvious to us) things that these unevolved people are confused about.
My point is - this guy's explanation sounds like a conclusion drawn from a limited understanding of how things really are. But IANAQP (I am not a quantum physicist)
Given that we discussed this in college physics, 15 years ago, I somehow doubt that Dr Deutsch designed the test.
Apache guy, Open Source enthusiast, runner
I just wonder if the laws of physics in parallel universe can be different too.
This interpretation is championed by many of the leading physicists. For example Deutsch and Murray Gell-Mann.
This is not quite what it seems. The interpretation may be mathematically used by many of the leading physicists, but not that many actually believe its really true, like Deutsch.
Damn, I've a Green laser pointer.
As seen on ThinkGeek.
is neatly explained in this stanford page.
Dunno if anyone mentioned it, but Michael Crichton's Timeline was based on time travel using the concept of parallel universes. Crichton neatly details an experiment to show the principle of entanglement. (sad that the movie did not deal with the science at all) Read the book for some nice fun with this concept.
"When the only tool you own is a hammer, every problem begins to resemble a nail." - Abraham Maslow (1908-1970)
A photon isn't a particle, it isn't a wave. It's a photon. So many people don't understand that.
So when a bunch of photons show up as an interference pattern, they think of it as waves and the model produces accurate and useful results. When people knock electrons off atoms with gamma rays, they think of the photons as particles and the model produces accurate and useful results. When the two models come together, people have the hardest time understanding it because they forgot the most elementary rule of models:
ALL MODELS ARE WRONG.
As I understand it, under the standard model, we figure out if a photon interacts with another particle by integrating over the set of all possible paths the photon can take in the meantime, producing a probability. That seems like a pretty sound model to me. Does this model require more than one photon to explain diffraction? Nope. Does it talk about waves and interference? Nope. It doesn't mention parallel universes either. This is the model that scientists started using when they realized that both the particle and the wave models were not only wrong, but they didn't always produce useful results.
The problem I have with the claim that this is proof of parallel universes is that parallel universes doesn't add anything to the existing theory. Now, if the parallel universe theory were to predict something disagreeing with the standard model, anything at all whatsoever, it would be useful. However, as it stands, I see the theory as just a more complicated explanation of the standard model. It may be true, but it doesn't seem useful, and usefulness is the only desirable trait in a model.
No scientist understands the laws of the universe, scientists don't even agree on the laws. They don't agree on string theory, on the existance of black holes, on the fate of the universe, on the presense of dark matter, or interpretation of quantum mechanics. If anyone were to ask me about any of those, I would give a resounding maybe. Heck, there are scientists proposing revisions of Newton's law F = m*a to explain discrepancies in galactic rotation.
I just get sick of scientists peddling useless but imaginative models to the public like this. That's what philosophers / fiction writers are for.
It shows that it it possible to get a particle (in this case a photon) to interfere with itself.
Where I come from, we call that masturba...never mind.
The third interpretation you're thinking of is called the "transactional interpretation" which was based on Feynmann's ideas but more fully worked out by John Cramer.
Jon Erikson, IT guru
But the observer is a passive receptor (in our case). I entirely sympathise with the objection - why is a human's retina the defining absorber, whereas those photons that strike other absorbing surfaces do not collapse the wave function.
As it happens I am a super-Copenhagen believer, that is, our function, as conscious entities, is to observe the many possible universes and 'select' the real one.
This defines consciousness, by the way.
Actually, we don't understand all the fundamental theories. That's why there is a dream to find a "Theory of Everything". But unless the present model is inaccurate or cannot explain some phenomena, the meta-theory doesn't change anything and there will always be questions how this meta-theory works. But this question belongs to philosophy, not to the science.
The simple answer for "how or why the quantum theory works?" is "We don't know and we may never know but we have some equations that can predict the experiments with incredible accuracy".
Save the bandwidth. Don't use sigs!
A human retian is not the defining absorber. Interaction with any macroscopic system collapses the wavefunction. This is why if you run the two-slit experiment but put a detector by each slit to watch for which slit the photon passes through, you don't get an interference pattern. The interference from the macroscopic detector at the slits collapses the wavefunction. Consciousness does not enter into it, that's just pseudo-mystical nonsense.
or truthful
's cat.
I don't agree, but then I like the mystical nonsense.
All you have done by putting a detector by each slot is to move the wave collapsing function back by one step of instrumentation. I realise this is an unprovable argument, but I think yours is as well. After all, I am not denying that you can take a photo of an interference pattern. You seem to argue that I am denying that.
"...Since we see the interference pattern here and there are no real things in our universe to explain it, the only rational solution is to posit the existence of real things in other universes."
...Since we see the interference pattern here and there are no real things in our universe [that I know of]to explain it, the only rational solution is to assume [that becase I know everything about our universe we can] posit the existence of real things in other universes.
Hmm... sounds like a God theory to me, let's fix it...
Personally I don't believe that Deutch knows enough about our universe to start saying that there must be others.
thank God the internet isn't a human right.
I can prove the speed of light isn't a speed barrier with ten rubber bands, a lego set, a rubber duck, and hot dog (red kind, not the white or brown kind).
Contary to numerous posts by people too lazy to read the whole article, this is not about the double-slit experiment. Halfway through the article we have the following:
Next to the two holes you've punched, make two more.
Deutsch interprets the results of this four slit experiment as evidence for parallel universes. A critique of this specific argument can be found for example here.
"Politicians and diapers must be changed often, and for the same reason."
Good to see people describing the quantum phenomenons as 'spooky'. Really. People tend to believe that everything's solved in physics. One has to keep in mind that physics only build *models of reality*.
Of course, in daily physics speak, one talks about 'the electrons that hit the surface' etc. because there is a underlying theory which describes most of the experiments with sufficient precision. Daily physics is simply more like engineering than thinking about the world itself.
But electron's are only human-invented concepts. Very successfull concepts, indeed. But only concepts. Maybe they're 'really resonances of some weird field' yet to be discovered. But what are resonances and 'this weird field'? They're also invented concepts. Concepts to aid 'understanding'.
Many of my fellows (I'm studying physics) just believe they're electrons which properties and formulas to describe them. I don't. I take them as always incomplete, yet successful and helpful models of reality. Maybe this is just an arrogant statement and my 'open-mindedness' now brands me a crackpot to be modded down.
But I am no crackpot. I don't believe in UFOs and stuff.
Regarding the 'multiverses': IMHO, one very important question remains: How you as yourself evolve in this multiverse. What decides which part you take in the multiverse? Why is it that you only see one universe, that you only exist in one universe? What decices where you/your conscience goes? Maybe this is the free will? I don't know but this bothers me.
I have invented a wonderful test for parallel universes:
Play russian roulette as long as you wish and you don't die.
If there are parallel universes in the way that they are created at each moment, every possible event occurs in some parallel universe.
Therefore, if you at some point die in one universe, you will keep on living in some others.
Since you can only observe that you live, it follows from the Anthropic Principle that if there is an infinite number of You, there is always a You that observed that you did not die.
So if you play russian roulette and get a *click* a thousand times with different revolvers (or even with pistols as they have a small probability of jamming), you can be quite certain that the universe is a branching multiverse.
Of course, if there is just a single universe, you'll just die.
This method can also be used for financial gain:
Notice that you don't actually have to play Russian Roulette, you can just wait -- people get killed mostly by accidents or random diseases such as cancers or heart attacks. So, if you live to be 1000 years old, there must be something really strange going on. (Of course, that's not much of a comfort if you have gradually demented to mental level of an avera cabbage.)
Ordinary audio CDs can function as a diffraction grating, too.
We got bored one afternoon in grad school (physics) and got into an argument over the track spacing on a CD. After about five minutes of yelling, I said "Wait a minute. We're reasonably smart **AND** we have access to lab equipment. We oughta be able to measure this for ourselves." And we went down to the lab, set up a (red) HeNe laser to bounce off a cd onto a screen behind it. A couple of measurements and a quick plug and chug later, we had our answer. Parallax introduced some error that was difficult to eliminate because of kwickee equipment configuration we had set up, but we weren't interested in more than an order of magnitude anyway.
"Lawyers are for sucks."
- Doug McKenzie
I thought that this kind of thing was just an example of Heisenberg's Uncertainty Principle. You more you know about the photon's speed and position the less likely it is to act in a predictable manner direction-wise.
"Computers are useless. They can only give you answers." Pablo Picasso.
My dining room, when the sun had set, was.
This guy has no clue how to write in the English language. First off all, DROP the ridiculous over-use of commas. This, is, not a, well formed, sentence.
Fine as it goes but perhaps you can explain how interference patterns arise when macro objects, like single buckyballs, are passed through double slits? Which has been observed. It seems to me Deutch's explanation is the only one that makes any sense.
See, this is what happens when you apply "interpretation" to science.
Quantum Physics is the single most successful theory in the history of science.
The interpretation of Quantum Physics is the single least scientific endeavour known to man.
It was fine for great physicists to propose these interpretations, but for anyone to accept them as "real", or to say one interpretation is more "correct" than another, is wrong-headed. What gets me is the people who then springboard off their favourite interpretation to make wild sweeping extrapolations with no scientific backing whatsoever.
Like, "this defines consciousness".
Crackpot? That's the first truly scientific statement I've read on the subject. Mod parent up!
And Michael Crichton's (I think that's how you spell it) Timeline.
... has counterparts in other universes and is ... interfered with only by those counterparts in that the parallel universes are identical to this one, but in another time, so the photons (if I understand correctly) would not be convergant. It neglects to explain that, of course. :-)
It diverges a bit from the theory that Every particle,
This is the real scientific deal, if you want to entanlge your mind with quantum mechanics and double slits experiments.
I'm too lame to have a sig.
Feynman (along with John Wheeler, I believe) at one time postulated that there was only one photon in the enttire universe; they later abandoned this position. Eistein, BTW, was a critic of the Copenhagen Interpretation, favouring instead a hidden variables theory.
The effect described in the article, while well known, is NOT DIFFRACTION. The 2-slit experiment you did in school is the one that demonstrates diffraction, and it's included in the article just so that you can keep it straight in your head!
PLEASE STOP MAKING POSTS OF THE 'This is just diffraction! I know all about _that_!' VARIETY!
Thank you.
Whence? Hence. Whither? Thither.
but I was more under the impression that the other photons might be moving off at 90 degrees to X,Y,Z instead of the addition of parallel universe "shadow" photons. Again, not a physicist - just an avid sci-fi reader (dangerous enough)
meh
Play Myst.
This sounds a lot like an old, old experiment described by Simeon Poisson with the intention to prove that light travelled as particles, and not as waves. The idea being that if light travelled as waves according to Huygens' theory, then there would be a tiny bright spot in the shadow cast by a pin-head in a narrow beam of monochromatic light. Poisson wrote a paper ridiculing this. Dominique Arago set up an experiment to show once and for all how the absence of a bright spot would disprove the wave theory -- and there, indeed, right in the centre of the shadow, was a bright spot .....
Je fume. Tu fumes. Nous fûmes!
The experiment sounds interesting, but I would never, never, never read anything this guy writes. It sounds like he has a very simple experiment that could be explained in about a paragraph and we had to make it hundreds of words. There is so much filler and useless extra language that I wanted to scream. Take a piece of paper with 2 holes in it. Shine a laser pointer thru it. Look at the wall. Put two more holes in it. Look at the wall again. Now I will explain the phenomenon.... There, I just rewrote his whole article. Argh!!!!!!
Cum catapultae proscriptae erunt tum soli proscripti catapultas habebunt
The computer in front of you is also nothing but a concept. It's just your bain's interpretation of the data coming through your senses. It's part of your brain's model of reality. Yet you'd surely call the computer real. Why? Because your brain's model works for it. The computer behaves as if it were really such a thing as your brain's model says.
Now, for electrons, it's the same: In all experiments so far they behave as if they were exactly what the theory describes. And therefore they are real, in the same sense as the computer in front of you is real.
The Tao of math: The numbers you can count are not the real numbers.
A lot of big If's, to be certain, but then we're already playing in, 'Amazing Stories' land.
-FL
Your explanation makes much more sense.
-FL
"David Deutsch, using an experimentally confirmed prediction from quantum theory"
yes, that is exactly what experiments do, they confirm (or not) predictions of theories.
what you mean is experiments do not confirm theories.
Yes, that's what I thought. The "mystical observer" that was spoken of in the post I replied to would indeed be mystical if it had anything to do with human consciousness, but noone (at least no physicist) has said that it has - that's only a misunderstanding.
That's why I posted my original reply, I thought it a bit unfair to talk about "mystical observers" and thus imply that the original theory is somehow pseudoscience. The difference between the two views is that one group (multiple-worlds) thinks that universes should be deterministic, and if they aren't we'll just define them to be, while the other camp is prefectly happy to accept that a thing can both be and not be in the same space in the same time...
In this context the third explanation that was mentioned (the one involving time) may not be so weird after all...
xkcd is not in the sudoers file. This incident will be reported.
> you need to make sure that only one photon leaves the laser at any given moment
Speaking of that, I have not yet heard a good explanation of how they determined that it was just one photon. Given the extremely fine grain of quantization, how can you possibly distinguish between one photon and two just by looking at the laser's energy consumption? What else could you be looking at? You can't measure it's size because it is too small. You can't measure it's mass since it has none. Shouldn't someone consider these things before betting the entire universe on this single experiment?
No wonder it is so hard to access a parallel universe. A firewire or usb one would be a lot easier.
Lets see...
Directly observe quantum behaviour of [something].
"Hmm...that's impossible according to my everyday experience."
Well, let's propose some fantastical explanation for this phenomenon.
See, that proves it! My wacko explanation must be right. No? Do you have a better explanation?
Of course you don't. Unless you understand quantum physics, and then you're hard pressed to explain it to anyone who doesn't.
The problem here is that on the scale in which we spend most of our lives, we simply do not observe quantum phenomena.
Trying to explain quantum effects within a classical paradigm is futile.
Lack of an easy explanation for something does not prove the assertion "It's magic, then.".
And while it does not prove "parallel universes" (buddy with the laser never did define "parallel universe"), it provides for good entertainment: Scrhoedinger's cat
"Reality is that which, when you stop believing in it, it doesn't go away." - Philip K. Dick
It was fine for great physicists to propose these interpretations, but for anyone to accept them as "real", or to say one interpretation is more "correct" than another, is wrong-headed. What gets me is the people who then springboard off their favourite interpretation to make wild sweeping extrapolations with no scientific backing whatsoever.
Well said!
This simply demonstrated that light behaves as a wave, by bending the light the resulting beams are out of phase, which will cause interference. This can be reproduces with light and sound. Such Interferense was demostrated in 1850 by Tomas Young in his Double-slit experiment. The reverse effect is that when the beams are combined in phase we get interferometry a.k.a Keck.
Finally, a Home Test that /.ers can make good use of. Unlike those Home Pregnancy Tests, this seems to really arouse some passions.
Parallel universe... right.
When as a child we did similar experiments, we explained the pattern that appears as wave interference. I didn't realize that it was evidence of a parallel universe.
Spock says: "I'm too sexy for my ears, too sexy for my ears".
I'm sure I'll be corrected if I'm wrong - but doesn't String theory prove the existance of alternate/parallel universes/worlds/whatever, and that they could be sharing the same metaphysical space as us? Sort of like having different channels in a TV? it's all in the same relative space, but there are different versions of it goin on all at the same time?
Of course, I could just know enough to shoot my alternate self in the foot with a laser pointer.
I'm not saying that parallel universes don't exist; I certainly think they do. But this guy's experiment doesn't prove it. --Or at least not as it was explained by the author of the article, who doesn't even seem to know the difference between a 'photon' and 'proton'.
-FL
I get all my scienific information from the one true authority: L. Ron Hubbard. I'll know if the "many worlds theory" is valid as soon as I find my official commemorative "Battlefield Earth" communications device and contact John Travolta, his cheif science officer.
This guys sounds like an idiot that doesnt understand the difference between a flashlight and laser is that the light is coherent in a laser....
( and wtf is 'fray' anyway, is this a new scientific term or something )
And no i didnt read the rest of it, if his knowledge was so limited in an area he was trying to show something with, i saw no point in continuing.
---- Booth was a patriot ----
And to finish, I'll be putting a ton of sand in my bathtub, filming it go down the plug and then watching the tape backwards!
did anyone ever consider the possibility that the photons of light may be being deflected off the sides of the paper(it may look 2d because its so thin, but its a pretty big area to a photon, and we really don't have lasers that go 100% straight yet - theres still scattering) and making an interference pattern? why the complex theory when something much simpler fits, especially when you would expect 5 slits(2 holes, so the photons not deflecting make 1 big light in the middle, and the deflected ones go off 1 on each side, most likly the outside of one side and the inside of the other, and visa-versa) - dunno, would just make sense, after all unless you have a material that absorbs all the light that hits it reflecting none whatsoever, you still have to worry about the reflection(deflection it could be called in this case with such a small angle)
-cory
While Einstein certainly helped to establish quantum mechanics, he did not like the Copenhagen interpretation because he could not bring himself to accept a non-deterministic universe.
It's rather interesting that after his work on relativity some people asked him about his religious beliefs to which he replied that they did not matter, but ultimately they did matter. Einstein later said that his religious beliefs were losely based on those of Spinoza. Basically Spinoza said that the universe is itself a part of God (this is an oversimplification though). To Einstein, if the universe is non-deterministic, then God must be capricious and random, which is something that Einstein could not accept.
Einstein believed that the probabilities that arise in quantum mechanics must result from incomplete knowledge of underlying hidden variables. However, Bell's work showed that there are some problems with hidden variable theories.
My only political goal is to see to it that no political party achieves its goals.
True. But the distinction I think he's trying to describe is like comparing Newtonian physics and Einsteinian physics. For most everyday stuff involving objects we can see and speeds easily measured, Newtonian physics work well (e.g. using F=ma to measure acceleration of a car). But as you approach the speed of light or supermassive objects, Newtonian physics' inaccuracies appear. The more extreme the conditions are, simpler models show their inadequacies and a more detailed accurate model is constructed. The same thing applies with electrons -- the basic model of an electron works reasonably well for things such as building simple electronic circuits and maybe particle collisions (I can't really say for sure, IANAP), but as more extreme conditions are explored, a more detailed model may be needed to explain electron behavior. Maybe it's like a fractal -- the closer you look at the edges, the more details that appear.
"No one likes working in a hamster wheel, and your shop smells of cedar shavings from here." - TaleSpinner
We've sure been hit with an overdose of crap science lately.
First the earth is going through global warming.
Then the earth is going through reduced solar irradiation.
Then all the crops are going to fail because aerosols are blocking all the light.
Now we have parallel universes from red photons?
I'm going back to the real world.
+++ATHZ 99:5:80
Quantum Physics is the single most successful theory in the history of science.
What about F = ma?
That Duke Nuke'em Forever is the most awesome game ever!
Unfortunately, it only runs in quantum computers, and I could not afford one in the parallel universe, because I was just as poor as I am now.
>Regarding the 'multiverses': IMHO, one very important question remains: How you as yourself evolve in this multiverse. What decides which part you take in the multiverse?
First off, IANAP (Physicist). But...
Nothing makes that decision. 'You' evolve every which way in the multiverse, and each copy has the same continuity of consciousness that you do.
>Why is it that you only see one universe, that you only exist in one universe?
You only see one universe because the interference between them only happens on very small scales. You exist in every universe that exists from the moment you were born (assuming that you are still alive in them).
>What decices where you/your conscience goes? Maybe this is the free will? I don't know but this bothers me.
Your consciousness splits just like everything else.
-- Give me ambiguity or give me something else!
>What decices where you/your conscience goes? Maybe this is the free will? I don't know but this bothers me.
Also, perhaps free will is just an illusion of the splitting. If for every choice you could make you actually do both, are you really making any choices?
-- Give me ambiguity or give me something else!
No, an imaginary one.
No, just the two.
I'm sick of parallel universe Bender always hoarding his cowboy hat over me.
Sorry, I couldn't resist referencing the greatest metaphysics joke of all time.
Yeah, thought about that, but for me the question remains. The "free will is an imagination" argument is circular and a too-simple answer, I think. What's this imagination?
Broadening from the free will to the 'self':
How comes that this (imaginated?) free self only sees *one* universe? Or, in other words, now, in the present, what decided why did you take exactly the way you took in the past?
I think this relates to Feynman's path integral quite a bit.
Me thinks the author forgot his 6th grade particle/wave light experiments.
In reading about this particular issue, I've encountered quite a bit of debate on the web; the most coherent explanation of this debate, I've found at www.hedweb.com, with an interesting 'appeal to authority' at this point. This page also explains why many scientists like the Many-Worlds interpretation of Quantum mechanics (it restores the deterministic nature of the Universe that dissappeared with Heisenberg and Schroedinger's work and eliminates the quantum waveform collapse along with many other paradoxical quantum behaviors) and explains why MWI is implicit in the concept of String Theory. Check it out, and do a little research before we start peeing on the theory...
Thinking outside my Head
>How comes that this (imaginated?) free self only sees *one* universe? Or, in other words, now, in the present, what decided why did you take exactly the way you took in the past?
Imagine that you actually took both paths in the past, but can only see that one you are in. Once again, I have to say that no decision was ever made - since both choice were actually taken. If you were deciding about where to go to lunch and the choices were Subway and Quizno's, the universe split and you actually went to both but are only conscious of the path you're currently in.
If you're asking why "I" only experince this reality, the other you can equally validly ask the same question.
-- Give me ambiguity or give me something else!
While the interference effect is certainly present for a single photon, there's no way you're seeing single-photon interactions with a friggin' laser pointer. I agree with the earlier posters--there's nothing any more mysterious going on here with the four-hole case than with the two-hole one. The interference patterns obviously look different when you have a different configuration of holes. If someone credible (e.g., someone that isn't claiming that Spock with a beard is holding his hand over the holes) says that the pattern is different than that predicted by theory, then I'll be interested.
Note that saying you'd expect the pattern to look the same with four holes as with two is nonsense--you'd expect the pattern to look the same with two holes as with one, if you didn't know about interference effects.
I don't know how the fudge you get parallel universi from the two-slit experiment. The conclusion is simple. Light behaves both as a particle AND a wave. Simple. Any wave passing through slits will create interference patterns, try it with water.
-73, de n1ywb
www.n1ywb.com
As it happens I am a super-Copenhagen believer, that is, our function, as conscious entities, is to observe the many possible universes and 'select' the real one. Um, no. The Copenhagen interpretation is one of strict Logical Positivism. It states that QM is a complete description of probabalistic outcomes of the experiments only, not of the objective reality of the 'objects'. The main problem that people have interpreting QM is they try to treat the 'objects' (e.g. an electron) like a macroscopic object (e.g. an apple). The Concious Observer framework was championed by Wigner, who although although he was a brilliant scientist, went a bit loony toward the end of his life. That happens to a lot of Quantum Physicists. I wonder why ..... ;-)
"What the masochist doesn't know can't hurt him."
Feynman's interpretation was called the transactional interpretation, and it involved all particles sending messages back and forth through time to each other, to determine how to react (I think). The book Q is for Quantum has a lot of good stuff on that.
:-)
./\
Anyway, the shadow particles in the article are just another physical interpretation of Feynman's path integrals. A path integral is just the sum of all possible paths that a particle can take.
Here's an explanation of the interference pattern in the double slit experiment:
Let's say that a photon does travel through both slits at the same time. Now, with the photon traveling through both slits, they follow every possible path. This diagram is just of three possible paths. That second level represents the slits, and the third level represents all posible paths. Now, if those electrons reach the slits at the same time, the will hit the target surface, right in between those two slits at the same time. Now, since it took the same amount of time, they won't cancel each other out like they would if they were out of phase (think of a sin wave and a sin wave shifted +pi added together, equals 0). Therefore, that point is brightest with twice the brightness of one photon hitting it. Now, move to the left or right, and it will take one photon just a little too long, and they will cancel each other out, turning that patch black. This is repeatable in both directions.
/
\/
\
Hurricane Ivan: A 17th century prison collapsed. All of the inmates escaped.
Let us suppose your simplification is correct.
Under my understanding of the religious views I was most exposed to as a child, (Baptist, Lutheran and the Jewish faith) God is "all things" and is capable of "all things."
Therefore, under those views, a multiverse/non-deterministic-universe would seem logical. It satisfies the path of least resistance in supporting the known nature of God.
(BTW...I worded this post the way I did in order to try to avoid stepping on anyone's toes.)
tasks(723) drafts(105) languages(484) examples(29106)
But I am no crackpot. I don't believe in UFOs and stuff
I've seen many flying things which I couldnt identify, due to lack of good optics, mainly.
I believe in stuff. It's what makes me go to work every day. To get more money, in order to buy more stuff.
Exactly. It's the Woody Allen phenomenon.
SharkJumper
The four slit model simply allows areas where like waves cancel each other out, causing yet another void which other radiating waves fill.
If he were correct I'd hate to think of what high tension lines were doing in these other universes, it would be like Alan E. Nourse's 'Universe Between.'
"Can there be a Klein bottle that is an efficient and effective beer pitcher?"
That diagram should be:
./\
/
\/
\
OK, nothing works, just think of a tree with 3 levels, 2 nodes in the second level, and an infinite number of nodes (leaves) in the third level, and that both nodes in the second level are connected to each node in the third level.
Now, just to add to my explanation above, imagine that each path has a cost based on how long it would take to travel that distance. When you iterate through the 3rd level nodes, and find out how much it would cost in time for the photon to travel to that node, you can then figure out if they are out of phase or not, and predict the outcome of the interference pattern!
I think I'm going to write that program!
Hurricane Ivan: A 17th century prison collapsed. All of the inmates escaped.
Aaaahhhh...the magic of marijuana...
It's like "looking busy" at your employment - it's actually easier to do real work than to fake it. - bmo
actually Einstein retaliated against the Copenhagen Interpretation. Thus his famous statement, "god does not play dice with the universe."
Which eventually led to the culmination if the famous Schroedenger's cat scenario. (the cat was eventually lost in another dimension).
once more into the breach
So this means my photo-diode (which emits electrons only when it "detects" a photon) is conscious?
-JS
Vanity of vanities, all is vanity...
This is by far the stupidest thing I have read in a while on slashdot. The results from the experiment have absolutely nothing to do with parallel universes.
Light is actaully a wave, (not paying any attention to photon duality at this point), and when you send the laser plane wave through the two holes (a plane wave is one that is pretty much straight and radiating in only one direction), the light from the two holes will radiate from all directions as heygens (sp?) emitters.
Now, if you can imagine, you have two sources of light each emitting a spherical wave in all directions. One property that a wave has that a clasical particle does not, is interference. If you think of a sine wave and you overlap it with another sin wave that is shifted by PI radians, then they will cancel each other out. Simmilarily, when the light is in phase, you will get a bright fringe, and when it is out of phase, you will get a dark fringe.
Another effect that exists is diffraction. This one is a little touher to explain, but it too will generate maxiums and minimums giving multiple fringe packets on the screen (in this case, the wall).
When they are talking about sending individual photons through the slits, this is a bit more difficult to explain, but basically works on the duality of light, in some circumstances acting like a particle, and in others acting like a wave. The light does go through all of the slits, and each slit will have an equal probability of having the photon in it. This is the light acting in its wave form. The moment you *look* for the location of a single phonton, the photon will collapse back onto the particle sense and give you an exact location.
This experiment has also been repeated with electrons, a known particle that also behaves like a wave, and simmilar results were found.
The photon marries its stepdaughter? Now you REALLY have me confused!
Gamingmuseum.com: Give your 3D accelerator a rest.
what would happen if you changed the speed of the holes?
by that i mean, if you had the holes parallel to each other and perpendicular to the laser beam, but moving toward or away from the laser source at sufficient speed.
would that change anything?
We better be careful, we don't want to start pissing of people in other universes. We're in enough trouble with *this* one!
Best Buy can have you arrested
...that so often, there are natural phenomena, for which good explanation exists (say, the wave-like properties of photons, which cause one photon to interfer with itself). And then, someone has to come along and say something along the lines of 'but, it's much more likely that it's because of parallel universes' or 'but i'm sure it's evil spirits from the other side' or 'and this proves that extraterrestrials exist and actually have taken over the bodies of our politicians'.
Spinoza's views, while derived from Judeo-Christian theology, don't really fit in with traditional religious views. One of his core ideas is that if God is perfect, he can't have any unfinished objectives. So God doesn't have desires, plans or intentions. Spinoza says that God cannot be described in anthropomorphic terms. So God, as Spinoza described him, does not do anything. He simply is everything.
It's also worth noting that Einstein's beliefs weren't exactly like those of Spinoza's. Einstein just said that his conception of God was similar to Spinoza's.
My only political goal is to see to it that no political party achieves its goals.
Yawn...I've already read all about it!
If the observed phenomenon were truly interference from "shadow" photons, then would we not experience similar interference involving other situations and other matter? Surely interference from parallel universes would not strictly occur in just this one instance where you have a laser pointer and slits in a sheet of paper casting shadows.
The answer that Deutsch presents is that the shadow atoms, present in the shadow photons, form a barrier
Finally! Someone who agrees with me on this! You have basically summarized the traditional philosophy of the scientific method. Prepare to be bashed by all those people who think that science defines reality reather than the other way around. Science tells us how, folks, but never why.
OTOH, I thought the article was a load of crap. Useful models may not be 'primary truth', but they at least have to be consistent and useful. This guy jumps to conclusions all over the place.
.. so I can try this?
The page no longer says "proton" anywhere on it: it's all been changed to photons!
Obviously this is pretty low-quality writing, and the fact that changes were made without any kind of little note or anything just adds to that.
zach
In particular I'd like to know, why does it have to be a RED laser pointer? The reasons given in the article "it gives a better shadow" and "it doesn't have other wavelengths to make it fuzzy" don't sound right. If it's really a parallel universe (and that's the wildest excuse for this experiment I've read yet,) it should work the same way with any wavelength, shouldn't it?
So what's the difference? The wavelength. Red is particularly prone to overlap / interfere with itself, perhaps? I just get this feeling that there's some really simple explanation for this, and people want to believe the most bizarre one.
Nix
to sell laser pointers
IANAQP. One thing I wonder though, if we assume there are parallel universes, why do we think that our lives would be different? If these shadows from the laser actually come from shadow particles going through one of three holes interfering w/ "real" particles going through the other, it would seem that the shadow particles are flying out in all respects exactly like the "real" ones - just half a mm away. Couldn't these parallel universes be exactly like "ours", only shifted left, right, up, and down (forward and back too?)?
Like I said though, I'm no physicist. But I'd appreciate info or links to info (non-crackpot of course).
What changed under Obama? Nothing Good
1. Get a big metal stockpot, or at least the biggest pot you can find.
2. Drop some xmas lights into the bowl, preferably blinking ones. If they do blink, try to pick a slow setting.
3. Fill a glass bowl with water and drops of vegetable oil/cooking oil/whatever sort of light, transparent oil you have around the house
4. Put the glass bowl on the top of the stockpot.
5. Turn off all the lights and stare at the ceiling for a couple of hours.
It really does make for some wild visuals, but you need to keep the water moving just a bit.
It may sounds kinda silly, but if you try it, you'll understand what I'm talking about. The way the lights refract through the oil and the shapes it makes are really incredible.
Deutsch formally described the quantum mechanical analogue to the Turing machine in 1985. Feynman did some earlier work on that, but Deutsch was the first to give a universal model that could be used to reason about quantum computability. (Although there were some problems with his model, so it's not as clear cut as the Turing machine.)
Just as a correction, Einstein didn't help come up with the Copenhagen interpretation, in fact he completely disagreed with quantum mechanics, hence his "God does not play dice with the Universe" comment.
By the way, IAAQP (I am a quantum physicist)
There is a neat applet at Physics 2000 that lets you simulate the interference pattern in a two slit experiment. It also lets you cange the distance between the two slits in real-time. Cool.
I know this because my wife is constantly changing places with her parallel self.
I don't know how she does it, but I can find no other explanation for such incredible personality swings.
Proverbs 21:19
(F = ma ran into a couple of problems a while back. Some guy named Albert studied the results of some experiments by some other guys named Michaelson and Morley, and decided that at high speeds, the concepts "m" and "a" started to get a little freaky. "d" and "t" were found to be pretty dicey as well.)
The parent post is right: quantum mechanics is one of the most successful theories in the history of science. By successful, I mean that it (a) accurately predicted measurements that were not explainable by previous theories, (b) has not predicted any results that are demonstrably incorrect, and (c) did all of this with a fairly simple (minimal) formulation.
Those three statements can be made about any solid theory, but QM has one unique characteristic. Unlike (say) Mendellian genetics, which challenges us with the difficult (but tractable) problem of "How did a biochemical mechanism for inheritence of traits ever come to be?", QM challenges us with "Why does the universe behave in a way which is contrary to our fundamental sense of reality?" This is not a knock against the theory, though. It just raises the deeper question: "Why should we assume that *our* fundamental sense of reality f-ing matters?" Despite almost a century of incomplete attempts to understand what quantum mechanics "means", the theory itself keeps on keepin' on - unfailingly accurate in its predictions, blithely indifferent to its metaphysical ramifications.
A different post in this thread makes the key point for grasping the various interpretations of QM: they are just *interpretations*. They have no bearing on what is "real" or "not real". All that is real (AFAWCT) is that the predictions of QM are accurate. Whether that means phantom universes, wave-particle duality, or little green men, is really of no importance until one of those interpretations leads to novel, verifiable predictions.
The article was not only an atrocious and pompous bit of writing, it was bad reporting. To represent this scientist's thesis as "novel" or even "scientific" just shows that the author doesn't know beans about the history of quantum physics.
Disclaimer: IWOAPUTDCB (I was only a physicist until the Dot-com boom).
It shows that it it possible to get a particle (in this case a photon) to interfere with itself.
Wrong. If you do the one-photon measurement you see that it goes through only one slit (for interference, it would have to 'split' and go through several slits at once). This topic was cleared a loooong time ago.
The first interpretation, created by Einstein, Bohr and other dignitaries of the time, was the "Copenhagen Interpretation" which requires an "observer".
Wrong again. It's not about observers, it's about measurement - or the meaning of it, which is interaction.
I believe Feynman has a strange third interpretation involving particles travelling backwards in time, that cancel out the waves of forward travelling particles at specific points in space-time.
Yet again wrong - and it's not Feynmann, either. The 'backward-travelling' particles are actually the 'forward-travelling' antiparticles - the negative energy sets the sign straight in the time phase of the wave function. And it comes from preserving causality in QFT.
The big problem with all these 'shadow' photons is causality. 'Seeing' is only a particular interaction - if they interact with something in this world (photons) there should not be a restriction on the interaction. Moreover, phase interactions can be measured - and if there are 'shadow photons' there should be 'shadow [insert particle here]' too - and phase altering can be measured really nicely for charged particles. Nobody ever saw that.
On the other hand, basic interference of light explains all this rather clearly. What a pathetic joke of an article!
...and for my next trick: I will prove the existence of God with a rubber band and a paper clip!
/^([Ss]ame [Bb]at (time, |channel.)){2}$/
Quit shining your laser pointer into our dimension!
"There is more worth loving than we have strength to love." - Brian Jay Stanley
'Fraid not, chief. Water waves are vast assemblages. Individual photons are ... well ... individual photons. The double slit experiment works when the photons are fired through the slits one at a time. This, if you properly grok it, is FUCKING WEIRD.
Is it fascism yet?
from http://plato.stanford.edu/entries/qt-entangle/:
"David Deutsch first showed how to exploit quantum entanglement to perform a computational task that is impossible for a classical computer."
Since we see many examples of light behaving as a wave and as a particle, I have to agree that treating it as two separate models is not the way to go. Now, I admit I know little/nothing aside from a few Physics classes while studying engineering, but these are things I think about when I consider the duality of light, even if they might be so ludicrous to some that they are correct. I do, however, find it difficult (at best) to believe in parallel universes/multiple worlds. So, alternatives that seem more plausible in my mind: Possibilities: 1) A photon is a particle that travels in a wave instead of in a straight line. This doesn't explain the results of the 4-hole 1-photon experiment. 2) The result of a photon travelling at relativistic velocities is a distortion much like a shockwave, except obviously not a physical wave as in sound. We already know that the detectable part of light is this wave phenomenon, so if there truly was a ripple from behind the photon, the wave would travel to the two or four holes and interfere.
You have understood nothing. The phenomenon is real and one of the strangest and most spooky things in physics
The poster to whom you are replying phrased his comment flippantly, but his criticism is correct. Deutsch's argument is, "I can't explain this, therefore it is inexplicable without introducing parallel universes". The conclusion simply does not follow from the premise.
Compare, "I can't think of any way in which you could build a ship out of materials that are heavier than water, therefore ships made of iron are impossible". An argument that was taken seriously once. Or Kant's argument that space and time were both (separately) absolute, because he couldn't imagine otherwise.
On the other hand it got me thinking: Perhaps an explanation for the quantum problem really is a parallel universe, but what's hsppening is that the photons are essentially 'phansing' in and out of the parallel universe. It's the phasing of the particles which determine their interaction. The Photons that 'arrive' at the dark bands are simply consistently in a 'dark' phase (i.e. in the alternate universe and, thus, non-interacting).
This would allow photons to keep their particulate state, and simultaneously explains their wave features.
Free Software: Like love, it grows best when given away.
Nothing makes that decision. 'You' evolve every which way in the multiverse, and each copy has the same continuity of consciousness that you do.
...
.
Your consciousness splits just like everything else.
I agree with you, mostly, but I think you skirted the parent's own point...
At this moment (we'll ignore the up-to-800ms but always greater-than-50ms lag between consciousness and physical reality), how many universes do "you" consciously perceive? Not "you" in the abstract multiverse sense, but "you" in the subjective sense. I only see one, basically consistant, universe around me.
So, to go back to the parent's point, if each quantum event in the universe causes a sort of global fork(), what determines which PID our consciousness gets?
In more physical terms, why can we not tell the difference EWG and Copenhagen? If the state vector collapses, why; if it doesn't, why does it "look" like it does, to us?
Actually, Einstein was adamantly against this view of the particle/wave phenomena. He essentially felt that quantum mechanics represents an excellent statistical representation of what happens on a small scale, but that the statistical methods used to model quantum physics are not at all what really happens. This is where his famous quote of "God does not play dice" comes from. He felt that everything was deterministic, not probabilistic, as the Copenhagen Interpretation requires.
Makes for some fascinating implications. "Quantum computers" are predicated on this probabilistic nature of reality. I suppose we'll finally get the answers to these long standing questions when someone is able to build a fully working QM computer and not just the "toy" structures that are built now. It'll be interesting to see what's really down there- a fantastically fine grained deterministic fabric of space, time, and matter... or the QM perspective of a continuous realm.
Lots of little clues everywhere, and I'm sure it'll all seem obvious in retrospect. But right now, it's a pretty fierce debate.
Yawn...Was this "experiment" done in a vacuum? no. Any particle can interfere with photons. Im sure some simple explaination is the photon hits other molecules, passing on a little energy sending them in the same direction to pass through the slits. Am I wrong? Isnt a photon just an excited electron? Or another small particle?
People want so bad for there to be a somewhere else...
The universe works the way it does because it HAS to. There is no need for all the extraneus (sp?) BS. It is a simple answer. If it didnt work this way, we would not be here to talk about it. The physics community hasnt even explained Gravity fully and they are worried about another universe.
Discovery and exploration is a good thing but using a cheap laser pointer in dark room will never amount to anything. (Other than pissing off the rest of the movie patrons)
This is not a Sig.
This is why if you run the two-slit experiment but put a detector by each slit to watch for which slit the photon passes through, you don't get an interference pattern.
Umm... Isn't that because the photons don't make it past the detectors in order to create an interference pattern?
>>As it happens I am a super-Copenhagen believer
I'm more of a Skoal man myself, but let's get back to our discussion of Physics...
I am fairly ignorant about a lot of physics, but could it be that the wave frequency of the light is modified slightly where the photons the edges of the holes, refracting and slowing as it passes through the top layer of atoms around the hole edge?
/shrug
Or perhaps since so many photons are streaming at the around the same wave frequency in the same direction, that photons actually DO interact with each other, but under such circumstances they resonate and create an unusual wave pattern?
This was actually covered on Futurama season 2, The Lesser of Two Evils, when Bender runs into (techincally, runs over) his twin Flexo, a twin with a goatee... shortly thereafter, a priceless tiara goes missing, and Flexo is the suspect...
In the end, it turns out that the Evil Bender robot is Bender after all...
Alain Aspect has performed some associated experiments which underline just how strange the
.....
single-"particle" case is.......
Imagine the dual slit experiment using particles,
the atoms are specially prepared so that after
they pass through one of the slits (but BEFORE
they get to the measuring screen), they emit a
photon. These photons can be detected by a
pair of detectors , thus measuring which
slit each atom passed thru.
1. If you run this experiment without the
photon detectors, you get the interference pattern
2. If you switch the photon detectors on and
record which slit each atom passed thru, the
interference pattern vanishes
HOWEVER
3. If instead of detecting the photons immediately
you let them bounce around in an internally
reflecting mirror system until AFTER the atom
must have got to the measuring screen, then
1. and 2. STILL APPLY. Even if you do not detect
the photons until after the atoms must have
got to the measuring screen, the interference
pattern still ONLY appears when you choose not to
determine which slit the atom went through.
I believe this experiment supports Feynmans
time-reversed potential ideas.
The thing that always made Schrödingers cat seird to me is that the cat is not counted as an observer of itself. I may not have seen if the cat is dead or not, but the cat sure has. So hasn't it collapsed the wave function? Would it be different if it was a human in the box?
Hi,
I'm a stupid slashdot idiot who thinks he is the authority on every subject. I didn't RTFA but I'm going to complain about it or point out any problems with my (mis)conception of what the author may or may not be trying to say. I have no education in physics but I'm going to spout a lot of stupid bullshit anyway, since my idle speculations are always insightful.
thank you for reading.
... what my dot.com venture actually made some money? I'm broke.
I've found that my posts don't format quite right w/o a sig.
Rich
Roughly in chronological order are: :)
The original Copenhagen Interpretation
Bohm's Interpretation
The Many Worlds Interpretation
The Transactional Interpretation
My own Aethereal Interpretation (blatant plug
Now that you've discovered the secrets of the universe, perhaps it is time to work on the great mystery of the English language.
people are going blind because of laser beams which appear out of nowhere!
and to think, there's a parallel universe were michael jackson is normal, it boggles the mind.
Or perhaps, some of the photons are making it through to the wall and since angle of incidence equals the angle of the dangle, they bounce directly back the exact same path - striking oncoming photons that careem off in obtuse directions losing so much energy from the collision that they do not strike any other object. This will account for the absence of light (some might say "shadow") and the absence of a scattered red spot somewhere else in the semi-dark room.
Ah, but what if no one was looking at the detectors? Could they exist in a superposition? That's the paradox of Schrodinger's Cat.
And what exactly is a "macroscopic" system? Is it not composed of quantum particles?
Collapsing the wave function when it interacts with a "macroscopic" observer is no more of an explanation than interaction with a "conscious" observer: neither "macroscopic" nor "conscious" are properties that are defined within quantum theory.
Bringing consciousness back into it at least brings us back to an oft-forgotten principle: all physical law is simply a means of grouping and prediciting observations that we (conscious observers) make about the objective universe. Any interpretation past that point is dancing on thin ice.
Tom Swiss | the infamous tms | my blog
You cannot wash away blood with blood
I Am Not A Particle Physicist.
That said, I'm a better particle physicist than Michael Chrichton. The crap physics he uses in the book are absolutely terrible. Even (especially?) the time travel is poorly thought out. I heard the movie was worse, and I couldn't bear to watch it. Please don't recommend this book as a good example of anything other than poor writing.
If you want good time travel, read "Timemaster" by Robert Forward. The writing isn't super, but it's a lot better than Crichton. For multiple universe stuff, I'm not really sure. Something is tickling my mind, but I can't think of anything specific.
Don't think of it as a flame---it's more like an argument that does 3d6 fire damage
No "trick" about it actually. The mathematics are
quite sound. As well Feynman came up with the Feynman diagrams and eventually the calculations to ground them in but the idea of antiparticles as particles moving backwards in time comes from Dirac. Feynman simply took it to a "logical" conclusion and using his different "tool box" developed a completely different(but equivalent) way of looking at quantum mechanics.
In the Intelligent Design school of thought so-called scientists look at the world and in essence say "I do not understand, therefor God." We now have a fellow modifying this to read "I do not understand, therfor parallel universes." Lovely.
Someone (Bradford DeLong?) mused to the effect of (my own paraphrasing follows): how much lab equiptment does one need in order to say "I do not understand, therefor God?" Now we know.
Cheers,
Scott
Please stop playing with the light switch!
It was a few hours ago I read this article, but here's an idea:
Open and close the extra pinholes to send morse-code message to the alternate universe. See if you get a reply.
"Would it kill you to put down the toilet seat?" -- Maya Angelou
He has rediscovered the fact that light has a dual state and can interfere with itself as if it had choosen different paths. The story makes it sound mysterious and previously unknown and that the only answer is parallel universes (the story says that it explains why this is the only possibility but it actually fails to do so). It then gives a two-sentence characterization of criticism for the conclusion as "how do we know it isn't caused by something we don't understand". Crap I tell you! We know what causes this and we understand it well enough to model it. I can't say we understand WHY matter acts this way but we don't understand why anything about the universe is the way it is.
up here in canada, we're switching to hex
The Neo-Bohemian Techno-Socialist
He didn't give enough information for you to onclude he understood nothing. It's quite obvious the story has some, uh, issues. Rather than explaining that we know what causes the phenomenon and that it has been well studied for decades it tries to make it into "proof" for parallel universes. It is not. The story makes a horrible characterization of critics who don't agree with that conclusion. You simply can not call that proof.
Something, obviously, is blocking the light from casting the shadow.
I ain't no research physicist, but I didn't know you could block light from casting a shadow...
I mean, not creating a shadow is a matter of putting light in that spot, which is the opposite of blocking it, right? That is to say, the shadow's there to begin with and you could block the light from eiliminating the shadow, but not from casting it...
Somehow it just doesn't amaze me that adding more points for light to come through seems to elimnate some shadows
Because why this happens is pretty simple
Light is a wave
if you add two peaks together you get a larger peak (sine wave + sine wave)
if you add a pitt and a peak together, they cancel out (cos wave + sine wave)
so the extra slits just cause the light to intefere with it's self AND to intensify it's self at other points
the same experiment can be done wiht a plank of wood with slits in it and a bathtub
you'll notice certain waves cancel themselves out and certain ones add together
the parralel universe thing is a funny idea but the article was labled funny afterall
The Neo-Bohemian Techno-Socialist
The so-called virtual light (which has only a phase-shifting effect on normal light -- so it's invisible) emitted/absorbed from the paper is constantly generating virtual light patterns on the wall in standing waves. If two holes are punched in the paper, the virtual light pattern from the holes ends up missing in the virtual light pattern on the wall. The phase pattern contrast is then illuminatable coherently, through the holes in the paper.
To put it more simply, the phase of light emitted is shifted by virtual light from a pre-existing absorber -- the wall. Makes more sense than Cramer's absorber theory to me, but again I think it's basically the same thing, but without necessarily invoking particles moving backward in time.
Virtual light would be basically another way of looking at QED, I'd say.
a) We already knew that the duality held up with single photon emission. We already knew that photons, in effect, interfere with their own probability waves. This can, and has, been explained without multiple universes. This in no way proves multiple interacting universes.
b) The experiment actually doesn't do that. They are using a laser pointer which emits millions of photons. There is no way to check for self-intereference with this experiment. At most it is showing diffraction patterns based on the wave nature of light. The 1800s are calling and they want their experiment back.
Consider an unstable nucleus which decays into two gamma ray photons emitted in opposite directions, each with opposite polarizations. Now place two polaroid filters on either side of the nucleus each at 90 degrees to the other an equal distance from the source. Now the first photon has a 50% chance of passing the filter but what is interesting is that the other photon ALWAYS does the opposite to what the first photon does.
To more clearly illustrate this think of trying to reproduce it with two separate computers. You can write any program you like to simulate this system and set any initial conditions and propagation laws that you like the only rules are that after an initial set up the two computers cannot communicate and you can't fix the random number generator's seeds (used to determine if the photon passes the filter)! Without communication between the computers it is impossible for them to always produce opposite pass/absorb results.
Modern physics forbids communication faster than the speed of light yet these photons are each moving in opposite directions at that speed. So how can we resolve this? Certainly some sort of "pre-knowledge" would work here - just as it would for the double slit experiment described. However I do not see how "Many Worlds" would help here. Thus, although to my knowledge, we have no clue how to explain such "pre-knowledge", it does seem that some mechanism like it might be what we are missing from QM and not a Many World's approach. The one thing I think all physicists can agree on though is that we are clearly missing SOMETHING!
This experiment can be done with waves in water and a dam with small openings, with similar result. I think "science" is a slightly misinterpreted by the author of the article.
Particularly amusing is his misunderstanding that this will only work with _red_ light... It works with any light, but due to varied refraction of the different wavelengths of blended/white light, lasers should illustrate the interference much clearer (since they emit only a single wavelength).
The mindboggling thing about the double-slit experinment is, that light of a certain wavelength can only be broken into pieces with a finite amount of energy, you cannot split a photon. And yet a single photon (an indivisable amount of electro-magcanetic energy at a certain wavelength) interfere with itself, generating an interference pattern when passing though a "double slit".
SLOGEN [ http://ungdomshus.nu : Sebastian cover music]
One implication may be that people in the other universe are conducting the same test at the time - creating the light that interferes with our light. Therefore I hypothesized that it should be possible to communicate with them. My proposed test was simple, set up the light test and then wave your hand in front of light to send morse coded messages.
Eureka! It worked. I successfully sent the morse code message "Hi" while receiving the message "Hi" back. Then I sent the message "Please stop testing, your light is messing up my test". Apparently our universes are TOO similar because the folks in the other universe had the same thought.
The universe I was conducting the "Light Test" with is so similar it is boring. However I now have proven that much larger particles can interact with extremely different universes! There is now the "Dryer Test". The "Dryer Test" is much easier to perform. Place matching socks into the dryer and occasionally one sock will achieve sufficient energy from bursts of static electricity to jump into an extremely different parallel universe, being attracted by the other universes lack of socks, or negative sock state.
As a representative of abused Hampsters everywhere, I would like to register a formal complaint against the parent poster. As a simple experiment shows, any small, fuzzy animal could be used, including gerbils, guinea pigs, mice or rats.
End the cycle of hampster abuse!
HBH"Smart is sexy." -- D. Scully ("War of the Coprophages")
This is a common experiment in undergrad physics. It proves that light acts both as a wave and a particle. When light acts as a wave, it interferes with itself, and thus cancelling itself out. The same test can be done with a bucket of water and instead of using holes, tap the water with the ends of two sticks.
I am not a quantum physicist - but I want to be! LOL...
we are all one consciousness experiencing itself subjectively - bill hicks
Bravo, well put. Our *ideas* dont matter, the human brain is good at one thing, attempting to make sense of the information that it is fed by our senses. We feel an inherent compelling feeling to try to explain things away to such a tremendous extent that we will accept a solution that creates a magnitude more problems than it solves if it only fits the square peg into the round hole.
Like I said in an earlier post, what we're going to need is another genius to put the puzzle together with the pieces we already have, rather than try to fabricate pieces ourselves, just as Einstein did when he eradicated the need for a cosmological ether by creating warped space-time... BRILLIANT!
--J
Beer, now there's a temporary solution -- Homer Jay S.
I don't want to know how all this spooky quantum stuff works, just hurry up and get me to the universe where I own a bunch of BMW's and am surrounded by babes.
Table-ized A.I.
I see you've never studied quantum! The experiments that inspired quantum mechanics necessitate that we redefine how we interpret our experiments. There have been tons of alternate interpretations of quantum mechanics (Einstein tried hard to disprove the Copenhagen interpretation; look up the EPR paradox), and the study of these (check out J.S. Bell's experiment) has had a profound impact on physics and on the philosophy of science.
You're absolutely right to admonish us against calling interpretations "real", but some are definitely more correct than others. Many interpretations of QM lead to inconsistent results, ontological arguments, and violations of other rules in physics (like nonlocal hidden variable theories violating relativity). Furthermore, some introduce unnecessary baggage (many scientists place Many Worlds here; I honestly don't know enough to have an opinion), and this is generally considered bad science (insert witty ether comment here).
I live in one of those parallel universes. Please stop shining laser beams in my eyes.
I'm in the hole of the broadband donut.
linky
linky
linky
----
All of whose base are belong to the what-now?
BTW, nothing you wrote seems like a concrete basis for rejecting many worlds. All that a many worlds hypothesis has to say is that for every quantum event which has multiple outcomes, multiple universes are spawned. The resulting explosion of universes probably defines a new kind of infinity, but so what? It doesn't really affect the math in any one universe.
I bet if you made one big hole instead of 4 tiny ones, you'd have NO interference!
I believe that most of the confusion over quantum physics is due to the (mistaken) impression that a quantum particle is just a very small "thing", a physical object that you can point to and say "This is an photon. We'll call him 'Bob'".
The truth of the matter (as far as science can tell) is that particles do not exist in and of themselves, but only appear (or don't) when you observe them. When you shine a light, the light is not "emitting" photons, but rather is making ripples in the possibility field (the "proxy wave") that influences whether or not a photon will be observed at a particular point. Until a photon is observed, it doesn't exist.
The double-slit experiment isn't so spooky when you consider this wave aspect. Consider dropping two rocks of equal mass into a pool of water. Ripples will travel outward from the points of impact, as the energy passes through the water. Where the ripples intersect, the water level will be up to twice as high as the height of the individual ripples (constructive interference). At some points, the high point of one ripple will intersect the low point of the other, and they will cancel each other out (destructive interference). Essentially the same thing is happening with this experiment, except instead of two rocks you have two slits, and you measure the "height" of the light waves when they hit the wall.
As for the multiple-universe interpretation, it's no more or less valid than any other. All the various interpretations of quantum physics attempt to explain the unexplainable: what's really going on when we're not observing? Is there a "deep reality", independent of our observations? If a tree falls in the forest, does it make a sound? If we see a quantum particle, does that mean it was there when we weren't looking? Before we open the box, is the cat dead or alive?
The best answer known at this point is: we don't know, and we can't know, hence multiple competing theories (e.g. Copenhagen vs. Many-Worlds vs. Bohm, et al.). They're all just different ways of looking at the same uncertainty, and in that way, all equally valid. My current favorite theory is that quantum particles interact not in only in space, but also in time; the future influences the past, just the like the past influences the future.
It's the one where they discussed time travel. The best part of that episode was the discussion of the Nimtz experiment which showed the possibility of FTL (Faster Than Light) travel through Quantum Tunnelling. Now, only if I can get data packets to reliably pass through the tunnel in succession, I'll be playing the lottery.
"Good, Fast, Cheap: Pick any two" -- RFC 1925
>So, to go back to the parent's point, if each quantum event in the universe causes a sort of global fork(), what determines which PID our consciousness gets?
What I'm saying is that it gets both. There's a huge IMHO in front of that, of course. For every fork, there is an equally valid consciousness existing in both universes.
If the communication between universes is only possible on the scale of an atom or so, why would we expect to be able to experience them? We don't notice anything else that goes on at that level in our everyday lives.
I don't know if I really buy this either, but think I can see how it works.
>In more physical terms, why can we not tell the difference EWG and Copenhagen? If the state vector collapses, why; if it doesn't, why does it "look" like it does, to us?
Wouldn't quantum computing demonstrate multiple universes? All those calculations have to be going on somewhere...
-- Give me ambiguity or give me something else!
- There are an infinite number of possible futures.
- At any given instant, there is a divergent universe where you die and one where you keep on living.
- Your stream of consciousness will always follow the path where you lived (rather than died).*
Of course, this does not preclude everybody else dying, since the path you happen to be on likely isn't the one where everybody gets to live forever (since there are also infinite possible futures where you live forever).It also says nothing about how good your life will be. It may turn out that Viagra stops working after 175.
* - No doubt, this is where people will disagree. I think you should consider this alternate question before coming to a conclusion: If somebody invented matter transportation which broke you into atoms and transmitted those atoms to another place and then reconstructed them perfectly, would that construction be you? What if they substitute different atoms of the same element? Would it be different if just the atoms of the brain were preserved and no others?
My opinion is that your stream of conciousness is just the conglomerate of your memories. The answers are yes, yes and no. In all cases, YOU are the memories, not the matter. Since your memories are preserved YOU are preserved.
The meek shall inherit the earth, in 3 by 6 plots. - Lazerus Long
To which Niels Bohr replied; "Stop telling God what to do."
--If something I said could be taken two ways, and one of those ways made you cry, then I meant the other way.
Maybe someday you'll be taught that that was the Civil War, and not the "Revolutionary War".
That's just funny! You're trying to apply classical mechanics to a quantum world! That is what was cleared up a long time ago, that classical mechanics doesn't *work* in the quantum world.
The first interpretation, created by Einstein, Bohr and other dignitaries of the time, was the "Copenhagen Interpretation" which requires an "observer".
Wrong again. It's not about observers, it's about measurement - or the meaning of it, which is interaction.
But, what measures the particles? The observer!
I believe Feynman has a strange third interpretation involving particles travelling backwards in time, that cancel out the waves of forward travelling particles at specific points in space-time.
Yet again wrong - and it's not Feynmann, either. The 'backward-travelling' particles are actually the 'forward-travelling' antiparticles - the negative energy sets the sign straight in the time phase of the wave function. And it comes from preserving causality in QFT.
Sure, it's wrong, but it's funny hearing someone vehemently applying science incorrectly finally get something right, and something that's *advanced*!
On the other hand, basic interference of light explains all this rather clearly. What a pathetic joke of an article!
Gah, I'm gonna die laughing one of these days. Here, let me imitate you! Wrong! Bzzzzzzzzzzzzzzzzzzrt!This was solved a looooooooooooooong time ago! Hahahaha, erk...... [END TRANSMISSION] Sorry for the flame, I've just been studying up recently! Your post just sounded a lot like the guy in Pop Sci who told string theorists off over "designer" physics. Hehe
Hurricane Ivan: A 17th century prison collapsed. All of the inmates escaped.
The "Many-worlds interpretation" [..] gets rid of the need for a mystical observer by introducing parallell universes,
Uh. And parallel universes are less mystical exactly how?
Correction: the physics community hasn't satisfactorily explained gravity AT ALL. Warped space-time does not explain why a shotput feels heavy in our hand. In the October 2003 issue of Discover, Michael Martin Nieto, a theoretical physicist at Los Alamos National Laboratory in New Mexico, was quoted as saying, "We don't know anything. Everything about gravity is mysterious."
OK; here's a force that supposedly emanates from all matter, yet has no identifiable power source, does not decay or diminish over time, and uses no fuel. Whatever happened to Conservation of Energy? The orbit of our planet around our sun is as close to a perpetual motion machine as we have ever seen.
And don't try to snow me with that old Work Function dodge. Physicists would have us believe that gravity never does any work. That it requires no work to keep our planet from zooming off in a straight line into space. That a boulder being forcibly held down on Earth's surface requires no energy. They say that, since w=fd (work = force x distance), no movement means zero distance and therefore no work, therefore no energy required. They modify the work function equation (which was never intended to be a "work detector") to explain that Earth being held in its orbit around the sun requires no energy since the earth is moving perpendicular to the constraining source. The modified Work Equation gives a zero result; therefore no energy is required.
What a load of crap! Go outside whatever building you are in right now and try as hard as you can to push it to the east for 10 minutes. Guess what? According to this logic, you have expended no energy! Oh, never mind that spaghetti feeling in your arms and legs. You've expended no energy because the building never moved.
Please. These guys don't understand/can't explain the most ubiquitous, fundamental force in the entire universe, and use flawed logic to "explain" it, yet expect us to fall at their feet when they come up with these inane theories. It's easy to find a theory that explains only some of the observations.
--If something I said could be taken two ways, and one of those ways made you cry, then I meant the other way.
No; YOU don't seem to understand the difference between an observation and an interpretation. It doesn't "show that it is possible to get a particle to interfere with itself." All it shows is that a beam of single frequency light passing through two holes and shining on another surface will produce a banded pattern on that surface. Photons "interfering with themselves" (whatever that means) is just one possible interpretation of the observation.
--If something I said could be taken two ways, and one of those ways made you cry, then I meant the other way.
Paid by the word.
The Kruger Dunning explains most post on
Given theorem: Because a single photon can produce mutliple illuminations on a surface (when run through a double/quad slit experiment), we must be experiencing photons from a parallel universe and there would be some deterministic problems (but that's if we model the universe by determinism... if not then ok).
... in some instances we get lots of light, in others none at all. Since our results are consistent that we DO get multiple photons, this should be ruled out.
Problems: 1) Article neither explains nor gives reference to how they are certian a single photon is emitted and sent through a slit.
2) If there actually were parallel universes that somehow effected our universe by creating multiple slits of light on the refractive surface from a single photon, that would mean that we could visually see the effects of this other universe.
3) But, if WE were to see the extra photons one of two possible situations arrise.
a) Either the other universes would have to loose X number of photons or else the results would be random - See: Hume -
b) But, I would imagine that each parallel universe would get the same result (see above), so that must mean mutiple photons are being produced from a single photon in every parallel universe. This, of course, can't happen... if it could, we just discovered free energy! But if we were to suck photons out from other universes that weren't doing the experiment at the same time, we could, in theory, totally destroy the other universes by sucking all the energy out of them... or creating large voids that suck in energy (black holes? no...).
Thus, since it is impossible for this experiment to work with multiple universes (abiding by current laws of physics and conservation of energy), their conclusion is bull hucky.
Could somebody please tell me where...err..who I am?
Where am I?
Am I God?
See David Bohm and Basil Hiley's "The Undivided Universe". The "other" universes are not parallel, but rather simultaneous probabilities and implicate in what becomes the result. It explains why logic demands something like parallel universes, but explains it in a way that not only satisfies the theory but with existing math that actually works. Students of quantum theory will recognize Bohm as author of what is still one of the best text books on the subject.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
That's just funny! You're trying to apply classical mechanics to a quantum world!
:-)
actually, no. But I'll give you that the first part was ill-phrased/incomplete. If you want the gory details of why that self-interference idea of the GP was off:
to get the 'trajectory' of the photon is ill-defined. You can however measure instantaneous position - unfortunately you lose the photon in the process. Hence, what you can do is place a detector immediately behind each slit and do one-photon emission + signal correlation between the 2 detectors. There's no correlation, either one detector blinks or the other. Do that with detectors on the interference screen and you'll see the interference pattern as a long-time average. All this was done, btw.
to put it differently: you have all the possible trajectories from the emission point to the measuring point, subject to the constraint that they go through one of the 2 slits; each trajectory has a probability given by exponentiating the corresponding quantum 'action'. you compute the corresponding path integral to get the resulting probability amplitude for reaching the point of the measurement. The most probable trajectories are the classical ones, guess why?
clear now? or do you want me next to spell out how the collapse of extended states works?
But, what measures the particles? The observer!
haha! no. First, you don't measure the particle. You measure something about the particle - position, for instance. The detector breaks translational symmetry. If you get a signal, the particle was in a suitable eigenstate of the position operator. If not, tough luck. There are lots of symmetry-breaking interactions in the Universe and not nearly enough observers for all of them.
again, clear? (oh well, nevermind, feel free to flame me anyway, this is getting to be fun
I had the good fortune to be taught by Prof. Isham in the Foundations of Quantum Mechanics. He is a brilliant lecturer and, while his book cannot rival the lucidity of his lectures, it comes a close second.
you're so wrong it's hard to start debunking it all. Part of it is already in my other reply. So let me nitpick a little:
... what is a photon and what is a light wave? That was the whole beginning-of-QM debacle. Finally, with the probabilistic interpretation, the (whatever it is we call) wave is regarded as a probability amplitude of finding the (whatever it is we call) particle. And that closed the topic (well, not immediately; but it's pretty closed now).
... oops! it does, sometimes. Does it mean I can combine 2 electrons into one super-electron? err... no. And what happens if the 2 parts don't reach at the same time? do we split electrons with diffraction and measure pieces of them? *pending answer* so, the moral here is ... you're only confusing the poor readers who don't know what you're talking about.
Let's say that a photon does travel through both slits at the same time.
and here I was thinking you actually understood something about particle-wave duality. I should laugh myself silly. The 'photon' is the name for the particle-like behavior of light. 'going through 2 slits at the same time' is what only waves do. so the proper phrasing would be 'the light wave travels through both slits at the same time'. Now
Now, if those electrons reach the slits at the same time, the will hit the target surface, right in between those two slits at the same time.
good Lord, man! I take it you meant photons, but the nonsense is still the same. Let's keep to electron diffraction, it's more fun. You wanted to say the 2 parts of the electron probably, as it was supposed to be only one. How hillarious. classical mechanics indeed. I wonder if that works with 2 whole electrons
Therefore, that point is brightest with twice the brightness of one photon hitting it.
no, it's 4x brighter for the middle point in the 2-slit experiment. It's called coherent interference. 2x is for incoherent superposition.
No offense, but for how the way you were flamming my post, I expected more of you.
Thanks for the cheap relativity lesson...The original claim was "the single most important". You weakened it to "one of the most important". And thereby nearly prove my point.
I still think that F=ma is the most important, from the point of being used by the most people, for most things, every day.
The "Many-worlds interpretation", first thought of in the late fifties gets rid of the need for a mystical observer by introducing parallell universes, where entangled particles can still interfere with each other.
This is a common claim about the many worlds interpretation, but I don't think it's true. A many-worlds interpretation still has to allow for the results of the double slit experiment, and, AFAIU, that means that universes only split when an observation is made.
The parent poster and several others have hinted at a key part of the culture of physicists: it doesn't matter what it means as long as its useful. My Inverse Problems teacher mentioned that a certain scientist (can't remember the name) suggested that what the wave equation is really complex probability instead of our normal real probability. But, his ideas hadn't received much attention because it doesn't change the equation, just the interpretation. And, its only the predictive quality of the theory that is of real importance to most physicists.
No no no, I belive the Star Trek episode you are thinking of is:
... are ... four ... lights!"
"There
"Can of worms? The can is open... the worms are everywhere."
With all the talk and misinformation against Everett's many-worlds interpretation of quantum mechanics, I felt compelled to provide some more in depth information on the matter and its relation to this article. Firstly, there are about 5 major contending interpretations of quantum mechanics. You might ask, why we need to interpret quantum mechanics. "Because it is freaking weird," that's why. Let me use a classical analogy to explain how it is weird. Imagine system of 3 coupled springs as shown here, http://www.math.okstate.edu/~wrightd/3013/spring/n ode4.html#SECTION00040000000000000000 . In classical mechanics, any motion of the two blocks (described by the top system) can be described as a superposition (linear combination) of the bottom two systems, called the normal modes. This is true in both classical mechanics and quantum mechanics. The difference is in when we try and measure the velocity of one of the blocks. In classical mechanics, the block maintains nearly the same velocity before our measurement as it did afterwards (save for a tiny perturbation). Overall the motion of the system remains largely the same. In quantum mechanics, we find that the spring system can initially be in the top state, and then after a measurement it is in one of the normal modes! Now that's crazy. The motion of the system changed _drastically_ merely because I looked at it! This is what is called the "collapse of the wave function" ("decoherence" for you physics types) because the system collapses into one of the normal modes after being observed. The problem is initially we were in a superposition of the 2 normal modes. From this, 2 questions naturally arise: Q1.) What happened to the other normal mode after the wave function collapsed? Q2.) What was _really_ the initial state of the system? These are perfectly legitimate physical questions, but they are very difficult to answer. As a first crack at trying to solve this puzzle, a number of different postulates have been devised. Some of them we can see as "easily" testable (I use that term loosely), while the testability of others escapes us at this moment in history. These are called the interpretations of quantum mechanics, and like I said, there are 5 major/important ones, and I list their answers to the questions as A1 and A2 respectively. They are: 1.) Copenhagen interpretation. This is the most abstract. It says that we can only talk about probable states, and nothing more. A1.) The system randomly fell into the observed state as a result of our observing it. In other words, "The cat has some chance of being dead or alive and when I looked at it, it randomly became dead (or alive)." A2.) The system was in neither normal mode. Period. (Yeah, that answer sucks. Most physicist agree.) 2.) Hidden variables. This is the most classical. It says that it really was in one of the states, but we just couldn't observe it (yet). A1.) It was never in that state. A2.) The system was always in the state we observed. 3.) Anthropic. This is the least satisfying, IMHO. It basically says that if things were any different, then we would not be here talking about it. It doesn't really address the 2 questions directly, and is rarely used alone. 4.) Everett's many-worlds. According to several surveys, it is the most popular amongst those who understand it, http://www.hedweb.com/manworld.htm#believes . Basically, both normal modes exist simultaneously, but in different universes. A1.) An identical spring system in another identical universe (with another you) continues to move in the other state. These two universes existed before the measurement, but they weren't different until now. The fact that they both existed before hand caused the original spring system to be in a superposition of both states. A2.) The spring system of the other identical universe, interfered (not interact!) with your spring system, causing the initial state in both universes to be mixed. 5.) Feynman's advanced and retarded waves. Note: even Feynman preferre
I've got one of these:
7 /1 0376.html
http://www.escience.ca/genSci/RENDER/4/1017/102
And I've got no luck. Any chance of someone posting pictures of the test??
- Zav - Imagine a Beowulf cluster of insensitive clods...
... you just have an orthogonal universe.
"What you've got here is one of those there parallel universes. Yeah, I'm going to need to get some extra equipment out of my truck..."
"Reality is that which, when you stop believing in it, doesn't go away." -- Philip K. Dick
umm ... it looks like we misunderstood each other's intentions. So I guess it's my turn to apologize - I didn't mean to start a flame war. It's just that your nitpicking me lead me to believe you understood more about qm (which is rare on /.) and this post was too incorrect for that image. No offense, since qm can be quite confusing if you're not into it (and even if you are ^_^). And no, I didn't hunt you on purpose - 0 level is often enough interesting, as sometimes pertinent AC posts are too intelligent for /. mods or plain go unnoticed. I thought you were game for a fun argument, but I overshot myself, so again I apologize.
peace. And welcome to my freak list - if that's how you feel about it ^_^
Yeah, that's it!
Dark energy is causing the shadows to "go dark".
Those who sacrifice security to condemn liberty deserve to repeat history or something. - Benjamin Santayana
Thanks for the excellent link. Do you know of any more that go into variations on that entangled photons experiment? e.g. can it be done without a coincidence counter? or what if the polarizer was moved before p hits it, but after s is detected?, etc.
:)
The experiment they provide leaves me in a quandary, itching to modify parameters to understand the extent of the relationship between the entangled photons. Fortunately, their explanation was very clear, unlike many presentations which depend heavily upon mathematical details. I'm looking for similar explanations of actual experiments which can help me understand better.
In fact, it'd be really cool if I could put together such an experiment and play with it, but I don't think that is currently realistic.
I seem to recall Bohm as proposing a realistic quantum-mechanical ontology (pilot-wave & the non-local quantum potential, later with the inclusion of the implicit/explicit order) which had the strange consequence of implying the existence of empty wave packets.
It's about time somebody said this. All this stuff about universes 'splitting' is not a required part of the multiple universes theory at all. It's just as valid to consider that all of the universes existed beforehand. What you said about wavefunction collapse (and how the multiuniverse explanation removes the need for the concept) is dead on, IMHO. Well said.
The wave particle duality tells us that matter is both a wave and a particle.
In this case I think that although when represented as a particle, the bending of the beam is explained, the light must be represented as a wave to explain this. Consider that when there are two holes, the beam is split to form 5 bands. When The other holes are added, those photons are pushed along a curved path. Here is the important part:
By representing the photons as a wave, as the coherent laser light is bent, it is also shifted 180 degrees out of phase, cancelling out the two bands that are missing. I haven't got a laser pointer, so i can't check this, but the other bands may have become brighter, due to the laser light being shifted 360 degrees, and adding to the total amount of light.
When we have the unified field theory, we'll probably understand all this.
IANAP, so I could be all wrong on this. And even if i was a physicist, I could still be completely out of whack.
In other words, they believe it's true when it actually matters, but prefer to think they don't.
No, it means they use the set of equations consistent with the interpretation. Its nothing to do with whether its 'true' or not.
No kinetic energy has been imparted to the building, as the work function implies. No physicist in the world would claim that no energy was expended, however. The real question is where did the energy go. It was turned into useless thermal energy within the muscles of the idiot who actually tried your dumb little experiment, resulting from the spasmodic movement of actin fibers pulling on each other. You need to learn more about the different forms of energy before you are qualified to participate in discussions like this. Oh, wait, this is /.. Never mind.
"I'm so moist I'm sticking to the leather." -Kermit the Frog on The Late Late Show
Your confusion over the work function has been dealt with in another post. Just because you don't understand physics doesn't mean it's wrong.
"I'm so moist I'm sticking to the leather." -Kermit the Frog on The Late Late Show
>Whether that means phantom universes, wave-particle duality, or little green men, is really of no importance until one of those interpretations leads to novel, verifiable predictions.
How do you explain qbits without a many-worlds interpretaion?
The processing does happen; researchers made a 7-qbit "computer" and it worked.
Where did the extra calculations occur? The other states are being calculated, but there are too many of them for the quantity of storage used.
I don't know the meaning of the word 'don't' - J
how long till a scientist who hasn't had his head in a scifi book comes along and proves that this shadow interferometry is at the least naive at best
The analogy is fundamentally flawed:
... items are both waves _and_ particles at the same time (depending on the interpretation you choose to follow, but I'll gloss over that).
... their are points of likelyhood for particles to impact on. All the particles are identical in form. It is not to do with differences in the particles make-up.
... back to work.
Quantum effects don't appear to happen to items above the Plank scale (ie only affects small things - sub-atomic).
What is worse is that items such as photons and electrons are considered to be point items with no appreciable size, they are irreducible (not made of smaller parts) so bits can't fall off.
How we see things at the macroscopic scales of everyday life is hard to relate to the quantum scale
To put it another way, items are particles that have a probability distribution in space and time, they might be here, they might more likely be there. The diffraction pattern (the distribution of VWs on the screen) is caused by the probability of any particle appearing in a particular place being similar for all the particles
This, incidentally, introduces an indeterminancy into subatomic interactions ("will this particular electron form that part of the pattern or that part?").
And so a possible description (from the article) then appears to be that each electron is a multitude of electrons in parallel universes forming all parts of the pattern at once but that only one of those multiverse electrons is visible to us. This appears to be philosophy however as there is no clear test that can refute it.
Wibble wibble bing
[Yes I did quantum mechanics and quantum field theory at Uni, I wasn't very good at it but I enjoyed it. My 'field' (no pun intended) of preference is particle physics.]
I find your rant against the ManyWorldsInpretation of QuantumTheory funny, since someone already said that MWI is consistent with other theories, so your argument amounts to this: "Quantum theory does not make sense".
Welcome to the club. Not quite what you intended.
To put it simply, to get the probable results, you need under QT all states to exist, even the unlikely ones.
You could try to amend this by stating that there is some magic rule causing quantum collapse/measurements, for example you could have a theory which states sharply decreasing quantum effects for large masses, below what the theory predicts.
But I think you would break most of the math that way. And the math is neat. So to make things make sense the way you want it, you need to introduce something akin to epicycles. Doesn't mean your theory is invalid, it just isn't neat.
Highlander at everything2.com
I'm still trying to figure out what people mean by 'social skills' here.
Boy, we're doing a damned poor job of it, then.
Gosh, I think we use all of the laws of physics every day. I haven't seen where I can go to opt out of any of them.