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Quantum Physics Parts Ways With Reality
aeoneal sends us to PhysicsWeb for news guaranteed to induce headache in those wedded to the reality of, well, reality. Researchers from the University of Vienna have shown the violation of a stronger form of Bell's inequality known as Leggett's inequality. The result means that we must not only give up Einstein's hope of "no spooky action at a distance," we must also give up (some of) the idea that the world exists when we are not looking. From the article: "[Studies] have ruled out all hidden-variables theories based on joint assumptions of realism, meaning that reality exists when we are not observing it; and locality, meaning that separated events cannot influence one another instantaneously. But a violation of Bell's inequality does not tell specifically which assumption — realism, locality, or both — is discordant with quantum mechanics." From the Nature abstract: "Our result suggests that giving up the concept of locality is not sufficient to be consistent with quantum experiments, unless certain intuitive features of realism are abandoned." Only subscribers to Nature, alas, can know what features those are, as PhysicsWeb doesn't tell us.
The World Wide Web is dying. Soon, we shall have only the Internet.
sounds like some meetings i've been in
closing my eyes at the age of four i knew the reality around me did not exist, so nobody could see me!
If you ask me, most of the people studying this sort of thing lost touch with reality long ago...
This comment is always the first post, as long as you are observing it. That's because by observing this comment you are not observing any previous comments, therefore they cease to exist!
I like my coffee the way I like my women - roasted and ground up into little tiny pieces.
How are we in some way special that "observing" something makes it exist or converge to a single state or whatever? Are we not merely objects of matter that inhabit the universe just like everything else in it? Moreover, the universe existed before we were there to observe it. It seems to me that "observation" is a red herring. I prefer Penrose's hypothesis that it is gravity that causes superpositions to converge, which is why tiny objects can be in states of superposition, while macroscopic ones do not.
I found the following summary on the web from its conclusion:
"We have experimentally excluded a class of important non-local hidden-variable theories. In an attempt to model quantum correlations of entangled states, the theories under consideration assume realism, a source emitting classical mixtures of polarized particles (for which Malus' law is valid) and arbitrary non-local dependencies via the measurement devices. Besides their natural assumptions, the main appealing feature of these theories is that they allow us both to model perfect correlations of entangled states and to explain all existing Bell-type experiments. We believe that the experimental exclusion of this particular class indicates that any non-local extension of quantum theory has to be highly counterintuitive. For example, the concept of ensembles of particles carrying definite polarization could fail. Furthermore, one could consider the breakdown of other assumptions that are implicit in our reasoning leading to the inequality. These include Aristotelian logic, counterfactual definiteness, absence of actions into the past or a world that is not completely deterministic. We believe that our results lend strong support to the view that any future extension of quantum theory that is in agreement with experiments must abandon certain features of realistic descriptions."
_______________________
I may be a simple man but a breakdown in Aristotelian logic? What are they going to use to argue against logic? I would assume logic.
Except for ending slavery, the Nazis, communism, & securing American independence, war has never solved anything.
was created when I was born and will end when I die.
"It's so convenient to have a system where everyone is a criminal" - A. Hitler
you can find here http://arxiv.org/abs/0704.2529.
we must also give up (some of) the idea that the world exists when we are not looking
Does this mean that sticking your head in the sand actually works?
134340: I am not a number. I am a free planet!
this is a test to see if unread comments on slashdot really exist
if you are reading this, congratulations, you have participated in bringing this comment into reality
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
... for news guaranteed to induce headache in those wedded to the reality of, well, reality.
It's a no brainer that marrying a real woman would be more trouble than marrying a virtual woman.
The universe uses portal-based rendering. The only question now is, is it Direct3D or OpenGL?
We've known for a couple decades that EPR made local hidden variable theories extremely unlikely. The real competitors are non-local. Bohmian mechanics (de-Broglie pilot wave theory, really) is one such. Bohmian mechanics make all the same experimental predictions as normal Quantum Mechanics. Bohmians tend to think of Quantum Mechanics as a non-local theory that only appears local because you talk about probabilities instead of positions. The probabilities of Bohmian mechanics are actually just as local as Quantum Mechanics...
Not that Bohmian mechanics should be viewed as a correct theory. It's clearly an artificial construct. But it's a better theory than QM for the simple fact that it talks about particle positions instead of observers. One assumes, after all, that physics goes on even when physicists aren't there to observe it.
A site can still get slashdotted even if I don't look at it.
Engineering is the art of compromise.
Time to get some new words, because QM has gone off the deep end as to what those words they're using actually mean...Words with actual meaning are used in a way entirely separate from their meaning, because scientists, by and large, could not be bothered to coin genuinely new terms...Quantum Mechanics is a terrible term in and of itself...
That is because "spooky weird LSD-like shit goin' down" takes too long to say.
Table-ized A.I.
"quantum entanglement would be pretty cool if an applicable use was found for it.
Applications already exist, at least if you count the demonstration of instantaneous transfer of information regardless of distance. And this experiment is years old.
So yes, quantum entanglement is indeed pretty cool.
As I read it they're not saying anything about the universe not existing when nobody's looking.
Quantum mechanics has a set of descriptions of matter/energy that "feel" incomplete.
To "classical physics" thinking the collapse of wave functions of entangled particles seems to require either some faster-than-light communication between the entangled particles (to tell the far one about how the near one was observed - violation of "locality") or some hidden variable (to carry information slower-than-light from the point in space-time where they became entangled to the point where each is observed - "realism" would include this hidden variable as part of the particles' state). Quantum mechanics doesn't describe either. It just describes a situation where this sort of thing just happens - in a way that you can't use it to carry information faster than light from one spacetime location to another.
Lots of work is being done to see if quantum mechanics can be "patched" into a more classical theory, in a way that preserves realism and locality by figuring out some way that a hidden variable can carry, from the entanglement to the observation at no more than lightspeed, the information necessary for a classical mechanism to produce the same result.
This work shows that some simple experiments have already eliminated a very broad class of such hidden variable theories - to the point that "realism" patches involving hidden variables carrying additional information with the particles looks pretty hopeless. This is another step toward the "quantum mechanics really is all there is to it" viewpoint.
(Of course I Am Not A Physicist so I could be reading it wrong.)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
D6 63 0D 70 89 81 BB 8E 7B 7C 5F 5D 54 EA AB 73
As per the tradition in new-school quantum physics, the original article is of course available for everyone at arxiv.org: http://arxiv.org/abs/0704.2529. (Nature articles are a bit special -- they are submitted to the "preprint archive" after they are published...)
Quoted from the issue:
;-) experiment has to do with polarized photon pairs where the polarizations must be different. When one of the pair is tested for polarization, its state changes from a superposition of possible states to a definite one. The state of its pair-partner "simultaneously" collapses to the other state, regardless of the distance between the two. It "appears" that either information has been passed faster than light, but that defies the math' that seems to work well otherwise, that causality has somehow been violated, or that there are more variables involved that we haven't identified. The article describes an experiment that excludes some of the proposed variables.
"These include Aristotelian logic, counterfactual definiteness, absence of actions into the past, or a world that is not completely deterministic."
We've had many experiments that demonstrate concepts some people just can't handle. The "classic"
If QM didn't so accurately describe a large number of events, no one would care that it violates their preferred "reality". It's like with the "information loss" when matter/energy cross the event horizon into a black hole. The indeterminacy and apparent irreversibility are at odds with some peoples' concept of how the universe works (mathematically, QM-scale events should be symmetric with regard to time).
Personally, I'd suggest that clinging to QM-incompatible notions, regardless of how well they've served to date, is less likely to provide a resolution to the discrepancy than accepting QM results as a basis for determining a more-inclusive reality of which those notions are a special case.
"Observation" does not require consciousness. It could just be that one of the photons interacts with a polarization-sensitive field in space.
In fact, I have a degree in it.
... that's as much as I know.
Hey kids. Get a degree in something you love, like Latin, or poetry, or whatever.
Then go get a job doing your hobby, like computers (I'm not good enough to be a pro surfer). And keep practicing your love (yes, every kind of love).
This will prevent quantum weirdness like waking up at 35 and realizing you hate your life.
As far as the nature of reality
+1 fashionably cynical
Sheesh, evil *and* a jerk. -- Jade
I read this paper about 5 or 6 years ago and it bears directly on the parent article and Bell's inequality.
0 07.pdf
http://xxx.lanl.gov/ftp/quant-ph/papers/9906/9906
Since I can't read the parent paper outside of the abstract it is hard to say. But I think that these two papers disagree in their conclusions.
I have one question. If the Japanese Ministry of Agriculture is not in charge of Gundam, then who is?
"Or reality as we perceive it is the interaction of particles, rather than the particles themselves?"
Funny you should say that.
Ever since I started studying physics/chemistry in high-school (at about the same time, 5th grade or so), I stopped thinking of "matter" as the defining issue, and started focusing on interactions between them almost exclusively.
It makes no difference wether a particle/molecule/object actually "exists" or what "internal make-up" it has, the only thing you should ever care about is what types of interactions it can have with other particles/molecules/objects... nothing more, nothing less.
Well, the "knowing about possible types of interaction" issue kind of makes it almost mandatory to understand exactly what any entity is actually "made of", but that's a secondary issue... if you know how something behaves in any possible situation, regardless of what's inside... do you really need to know what's inside ?
Or, rather, if you know how something reacts to any imaginable interaction, would you have any actual means to determine without the shadow of a doubt "what's inside" ?
My personal answers are both negative: you don't need to know, and there's no way to know for sure.
Heh, here's the craziest thory: what if "space", "time" and "energy" don't actually exist (or worse, what if they're ALL discrete, not continuous) ?
Would we even be able to notice ? Or have we noticed that already (Planck's h) but can't grasp the concept ?
For all intents and purposes, the entire universe actually existing (on one hand) or being a completely fictional construct/simulation (on the other hand) makes no difference whatsoever.
So, basically, all what's left of reality is simply interactions between entities, not any of the entities themselves.
By reading this signature you agree to not disagree with the post you just read.
I am the center of the universe.
Why don't they just throw some more Tacheyons at the problem?
It always worked on Voyager.
Well, it all makes sense, if you think of it. Whoever is running this MMO we call RL, can't possibly have the resources to simulate every single particle all the time. So until someone actually goes and observes the damn thing, there's no need to actually spawn/instantiate it.
Think of going farming for copper and tin ore in, say, the Gold Coast Quary in WoW. A particular ore spawn point might have been spawned as tin (most often), or as silver (rarely) or not at all. Would it already be spawned and in memory, if noone was there to see it? Or would it exist only as a probability until someone actually gets in range?
Or say you're hacking away at a copper ore vein with your trusty cold iron pickaxe, like a good dwarf. Sometimes you get just a piece of copper ore, sometimes you also get 1-2 pieces of stone, sometimes you get a Shadowgem, or a Tigerseye or Malachite. Were they already there before you started to hack at the ore vein? Or did they exist only as a probability until someone actually gets that loot window?
Of course, once you got a certain set of ore, stone and/or gems, closing the window and hacking at it again, won't change it. It stays the same set of, say, 1 ore, 2 stone, 1 gem until you actually loot them.
I can tell you, the best gnomish engineers and mages have worked hard for an answer to those questions, but everyone came up empty. We just can't figure out a way to see what's there without seeing what's there. Even warlocks sending their Eye Of Killrog into the mine didn't manage to fool the system. That and the eye got killed by the bandits in the mine. The best priests whined... err... prayed piously to the great gods of Blizzard, and got no answer. Etc.
A polar bear is a cartesian bear after a coordinate transform.
Terrorists can't threaten a country's freedom and democracy. Only lawmakers and voters can do that.
In other words:
A known is provided by each observation. Each observation will yield information about the past as well, but until it takes place, that past is uncalculable, so from the viewpoint of the latest observer, they don't know anything about the past until the last observation.
The "waveform" is what actually? I mean, other than a statement about our state of knowledge and other than the worst concept QM has? Not a friggin' thing.
The cat is alive or dead. The waveform is your knowledge of said. The "collapse" is no more than an "Oh, my!" moment.
This happens for each observer (without the Oh, my for the inanimate ones, who really don't "observe" at all, only react physically in some way, but are said to "observe" so that it appears that the macro world indeed is anthropomorphic).
If the observer can be anything (a concept that is after the fact), then the inside of the box can be the observer and the cat was never in an unknown state -- only our knowledge of its state was.
Seems to me, they have gone overboard describing that "things that touch somehow, create a change". Wow. Deep. Starlight touching your retina morphs a pigment. Heavy.
No Virginia, you didn't make the star twinkle, it exploded last year. And, no Virginia, you are not powerful enough to have projected backward in time and made it twinkle just for you.
Math is a descriptor, both of the real and the unreal. Nothing more; it defines nothing, only lends voice to the description.
Does pi infinitely repeat? No, it has a value of 1. I'm just using base pi for convenience with circles. Makes balancing my checkbook a nightmare, though.
Sorry about the ramble. I just read a couple of QM books.
It has already been stated several times, but as it is kind of being drowned out by the noise, I will add my voice to the chorus:
Waveform collapse is not relative to the observer!
It might seem like it should be, because it is slightly more intuitive that way, but it is not. This is very important.
Your explanation is entirely incorrect, and you're kind of doing a disservice to those who read it an think they now understand QM a bit more, when in fact you have just led them further astray.
Well, yes and no. Mostly no. And I was indeed joking, and pretty heavy-handedly at that.
Floating point errors tend to be more chaotic and unpredictable. QM is actually quite predictable and you can calculate useful stuff with it. E.g., it's not just that an electron in a potential well sometimes "tunnels through" (or rather, due to uncertainty principle constraints, it might have enough energy to jump or it might already be on the other side.) You can actually calculate how many will tunnel, and under which conditions, and build for example a Zenner diode. Mere floating point errors don't act that predictably, or not in the same way.
The thing about QM is... well, that QM doesn't actually have a problem. You can calculate stuff with any degree of accuracy, and, assuming you can actually design an experiment to simulate an measure it that accurately, chances are you'll get the expected results. The QM has been better validated than pretty much anything else.
Most of the conceptual problems you read about it are, basically, not problems of QM itself, but problems of the human imagination. The only problem is trying to imagine it, with a mind and in terms/concepts that were not made for that kind of problems. It's like trying to imagine a Beethoven symphony in terms of shapes and colours. That big a problem.
The human mind and your everyday experiences are based on macroscopic, Newtonian experiences. That is really why you find Newtonian mechanics simple. Your intuition helps you there. If I say "imagine a billiard ball hitting another" or "picture a ball rolling down a slope", you can conjure that mental image right away. You have tens of years of experience with that domain, and a brain which evolved to deal with that kind of problems.
When you move to Quantum Mechanics domain, your imagination and intuition fail you. (And me too, so don't take it as being snotty or anything.) You can imagine a particle, like a billiard ball. You can imagine a wave. (E.g., think: raindrops on a lake.) You _can't_ imagine something which acts fundamentally and thoroughly as _both_ at the same time. You can work abstractly with the concept, because you're undoubtedly a smart guy, but if you actually tried to really _imagine_ it, you'd probably just get a headache.
The "problem" is that people instinctively try to reduce it to one or the other, but each has its own problems:
- Thinking of, say, an electron as purely a particle, just like a small newtonian billiard ball, gets out of hand very fast. It does all these things, like mysteriously appearing on the other side of a potential barrier, which just aren't very newtonian.
- Thinking of it as purely wave, popular as it may be, is almost as big a mistake. Whenever you actually measure a state, you get a particle, not a wave front. E.g., if you put a phosphorescent coated screen (like that of a CRT) in the path of the electron, you get a single blip of light, not a fuzzy cloud over the whole screen. It only hits exactly one atom or mollecule of that phosphorescent coating, not all of them.
At any rate, that is the only problem: trying to imagine it all in a way that makes any sense to your macroscopic intuition. Even smart people who know QM well have a problem there. When you apply your intuition to it, it just doesn't make any sense. So all sorts of funny metaphors are invented to try to describe it... in words and concepts that just weren't made for that, and to a mind that wasn't supposed to imagine something like that.
Well, and then there are the people who _don't_ understand QM. Again, not meant snottily, it's a very hard and abstract domain. If it gives experts mind-cramps trying to wrap some intuitive sense around it, you can imagine how hard it confuses everyone else. So a thousand times more bad metaphors and mis-understandings get born that way.
A polar bear is a cartesian bear after a coordinate transform.
I mean, Euclidean geometry, Riemannian geometry, Ricci tensors, topology, Lorentz contraction, Maxwell's demon, algebraic set theory, noncommutative geometry, and Quantum Mechanics were all instances of science following technology.
It's an impossible thing to quantify without some sort of rigorous definition of technology, but I'd say technology follows science as much as science follows technology.
Ben Hocking
Need a professional organizer?
Yes, well, you'll have to understand that this is second hand, what some prophet understood from God's dumbed down explanation to someone who doesn't even have the concepts to understand it all.
:P
Think explaining Linux or the Internet to my old grandma (otherwise a smart woman, but doesn't even have a computer) and see if you don't end up dumbing it down to "it's like some tubes" oversimplification to get it over with. Now think she goes forth and writes a book about it. Ouch. It's not going to be very accurate, to say the least.
I mean, I can just think God explaining a player wipe to Moses:
God: "So we just reformatted the hard drive and re-installed from backups."
Moses: "Uh, what's a hard drive, Lord?"
God: "Well, it's this thing, like a magnetic disc, where everything is stored. All you see around you is on it."
Moses: "So, like a flat platter lord? And it carries the whole world?"
God: "Ah, wth, yeah, the world is on a plate. Whatever. So, anyways, we reformatted it..."
Moses: "My Lord, what's a reformat?"
God: "We wiped it clean, really?"
Moses: "Wiped the whole world, Lord? How is that even possible?"
God: "(Gah, I'll never get to the bottom of it.) You know, rewrite it all... if you will, cover it all with the same value."
Moses: "With a value?"
God: "You know what? With water."
Moses: "Like a flood, Lord?"
God: "Yeah, I flooded the damned thing. Everything was cross-linked and corrupted anyway."
Moses: . o O (Damned? Corrupted? So the world must have been sinful and angered the Lord.)
God: "So, anyway, then we reinstalled the prototype files for everything from the backup and respaned them everywhere..."
Moses: "Curse this feeble mortal mind, Lord, you've lost me."
God: "You know, prototypes? Like a definition of each animal? A master copy of each animal, one per sex? Male lion, female lion, male zebra, female zebra..."
Moses: "So you had one male and one female of each species stowed away somewhere safe?"
God: "Yep."
Moses: "On a... what was the word, Lord? Backup?"
God: "Uh, a big boat. Really big boat. I told this guy Noah to put one of each there."
You can see where it's going
A polar bear is a cartesian bear after a coordinate transform.
There's a whole passel of improperly informed people yakking on about consciousness and its relation to reality and other ridiculous notions, specifically because people insist on confusing the necessary MEASUREMENT with the irrelevant OBSERVATION. Collapse of quantum wave functions requries interaction with another non-entangled wave function such as a measuring device. All of the results which support the inequalities tested and referenced here were produced using equipment which measured the phenomena and gave results well before any observation occurred. The parent, and the blurb in Nature both imply the mistaken idea by using terms that refer to a observer. Nature should know better. Everybody else that's really interested in understanding it should learn better. It makes the science much more interesting. But then it weeds out the semi-informed speculativists and the newage (rhymes with sewage) pseudoscientific-spiritual theorists. Being the vast majority, they obviously tend to revolt at the insistence on being correct.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B