100th Anniversary of Quantum Physics

EricR writes "On December 14, 1900, Max Planck presented experimental results in front of the German Physical Society and announced that they could best be explained if energy exists in discrete packets, which he called "quanta." Today is the 100th birthday of Quantum Physics."

Comments

100th?

[servoled]

Would it be the 102nd? Or am I missing something here.

Re:100th?

[Anonymous Coward]

>Would it be the 102nd? Or am I missing something here.

The number 100 is correct.

Slashdot is simply very late with the news this time.

Re:100th?

[MrResistor]

It's slashdot math. You know, it's just like how 50+2-1=49

Re:100th?

[grub]

It's 102 in imperial years, 100 in metric years.

Re:100th?

[pimpinmonk]

Nah, it's correct. In the spirit of Planck they correctly accounted for the transformation from numbers to waves to particles and back.

Re:100th?

[Anonymous Coward]

Nope, some people just can't add.

However, it is the 100th birthday of the first transpacific telegraph (according to this:)

The first transpacific telegraph was laid starting on December 14, 1902. The cable connected San Francisco and Honolulu with some 2,620 miles of telegraph wire. The cable was laid out by the ship, "Silverton", which left San Francisco on December 14 and reached Honolulu on January 1, 1903. The first message was sent on January 3, and the telegraph opened for public use two days later.

http://www.andibradley.com/whatya/dec14.htm

Re:100th?

[Henry V .009]

Oh ye of little faith!

delta E * delta t >= h-bar

Therefore, the slashdot editors are being careful about not determining the time too precisely lest Max Planck and the German Physical Society accidently obtain an energy with an order of magnitude anywhere between a butterfly's wings and a supernova.

Re:100th?

[AntiFreeze]

Well, you see, today is the 50th anniversary of the first April Fools' day.

Re:100th?

[doubtless]

Yes, it is the 100th anniversary, but we have problem zeroing in the exactly street address Max Planck started all this. However, scientists are pretty sure he was somewhere in Germany.

Re:100th?

[enderwiggen]

It's numerical imprecision... 102 = 100 for small values of 102 or for large values of 100

Re:100th?

[Anonymous Coward]

Looks to me as if they meant a tenth of a kiloyear. Where kilo year is calculated as 1024 years.

Re:100th?

[Anonymous Coward]

I think they probably got this article from a parallel universe where today is always the 100th birthday of quantum physics.

Or we're in a parallel universe where slashdot editors are really bad at math and spelling.

Re:100th?

[WPL510]

Nah- they just got backlogged on the submission queue. Anyway, though, there are some nice notes tracing the mathematical development of quantum mechanics (from a chemistry standpoint) on MIT's OpenCourseWare site: http://ocw.mit.edu/5/5.61/f01/index.html (and don't link- finals are coming up, and this site is too useful to me to be slashdotted!!)

And now to nitpick: Actually, the correct expression for the heisenberg uncertainty principle is Delta(E)*Delta(t)>= h-bar/2, meaning that the product of the uncertainties ("delta") in energy and time cannot be less than the quantity planck's constant "h", divided by 4*pi (not 2*pi, as stated in previous post). That is, if you know one quantity with miniscule uncertainty (time), the other must have a huge uncertainty because the two quantities cannot both be known with a high level of precision (see the MIT site above for a looooooooong explanation). The product of the two must be at least some minimum value (hence the joke in above post, for non-physics people. Kind of kills it, though).

Re:100th?

[Henry V .009]

divided by 4*pi (not 2*pi, as stated in previous post)

No, I'm right. But, so are you, interestingly enough. Anything within about a factor of 10 of h-bar is allowable because of the different ways of calculating those values for a wave-packet.

Re:100th?

[Have Blue]

Given that Slashdot time was 100 years and wall-clock time was 102 years, we can determine that Slashdot is moving at an average velocity of 2.941 x 10^8 meters per second relative to the news source. No wonder no one has time to read the article...

Re:100th?

[z)bandito(_X]

it was one hundred, until someone looked at it and it changed...

Re:100th?

[DrLudicrous]

Yes, but the canonical expression for uncertainty principles is in general hbar/2, not just hbar. Not that this really matters, since like you say it is the same order of magnitude. In general, the non-physicist scientists will use the former over the latter as a matter of convention.

Re:100th?

[Tablizer]

It's slashdot math. You know, it's just like how 50+2-1=49

So *that* is why my Karma is shit. All this time I thought I was just a loser troll. Now I feel better.

Re:100th?

[DrLudicrous]

Are you using special or general relativity? The special case would be inapplicable due to the rotating frame...

Re:100th?

[Henry V .009]

h-bar/2 is used when you are using expectation values of the wave equation to calculate the delta terms. Bohm, amoung others, uses h-bar. There is no set way to write it, because the expectation values aren't always used. If you are going to use the equation, you simply need to know what you are doing with it. I could care less what the chemists call cannonical.

Re:100th?

[DrLudicrous]

In essence, I concur. It's a moot point, except that those outside of physics don't grasp why, which confounds me given the orders of magnitude argument.

Re:100th?

[Black Copter Control]

Or we're in a parallel universe where slashdot editors are really bad at math and spelling.

hehe.
It took me a while to figure out that this universe would be parallel to itself... (which makes parallel an equivalence relationship).

Re:100th?

[Black Copter Control]

Anything within about a factor of 10 of h-bar is allowable

Makes sense -- given that we're talking about the uncertainty principle....

Re:100th?

[riflemann]

You can blame Heisenberg.

Re:100th?

[Zork the Almighty]

It's the 100th aniversary of quantum physics, and about the fourth aniversary of Enron math ! Woo Hoo !

Re:100th?

[popmaker]

Yeah, but years have an annoying tendency to slip by and disappear. We'll just have to stick with an approximation worth 2 significant digits, so it so until the year 2005, it will be quantum physics 100th birthday.

Re:100th?

[jaavaaguru]

Haha, I like the sig ;-)

Re:100th?

[TheAncientHacker]

Nah. In quantum terms, there's an equal probability that 2002-1900=102 as 2002-1900=100 or 2002-1900=98. In fact, it could be said that every year is simultaneously the 100th anniversary.

Yes, I'm tired of quantum theory being used as a justification for bad science...

Re:100th?

[Jamesie]

are you sure?

Re:100th?

[JebusIsLord]

You cannot both know the data and report on its aniversary at the same time, only one or the other via the uncertainty principle.

Re:100th?

[babbage]

This is quantum physics we're talking about -- the true answer is indeterministic. If you try to measure it, you stand some probability of getting these unexpected results :)

Re:100th?

[Anonymous Coward]

roflmao. Oh dear. funny. MOD THIS UP.

Re:100th?

[anthony_dipierro]

Also, Delta here represents standard deviation. It can be calculated exactly from the Schroedinger equation.

Re:100th?

[anthony_dipierro]

Yeah, but it's not exactly true. There is an exact uncertainty, which can be calculated using the Schrodinger equation.

Richard P. Feynman said...

[bartash]

"I think I can safely say that nobody understands quantum mechanics."

Re:Richard P. Feynman said...

[missing000]

Just as slashdot does not understand "time"

Re:Richard P. Feynman said...

[grahamlee]

He also said "look at me, everything I do is brilliant, you must listen to me, BTW I designed the H-bomb whilst hacking into someone's safe isn't that cool?".

My favourite quote from a quantum mechanic was Einstein's "Two things are infinite: the Universe, and human stupidity. Oh and I'm not so sure about the first one." If you're worried about the phrase quantum mechanic being applied to Einstein, I suggest you read about the photoelectric effect.

Re:Richard P. Feynman said...

[FosterSJC]

That is because, I believe, quantum mechanics is inherently incomprehensible. Kant informs us that we can never perceive a thing in itself since any perception is a psychological process that somehow or other colors the impression. But we can perceive directly and indirectly. That is, we can be assured that there is a "thing" we are viewing when we view something. But with the electron or the photon, these things are beyond are perception. Thus, our psychological processes (the a priori forms of our spatial and temporal intuitions) cannot fully operate. That is how we get something like the results Davisson produced, viz. a simultaneous particle-wave. He showed that a cathode ray firing one electron at a time still produces an interference pattern. That means that though the electrons are fired discretely, there is a wave pattern formed perfectly alike to interference patterns. So the electron either knows where past electrons went and future electrons will go, and governs itself accordingly, or there are rules that apply to the things outside our perception which are contrary to the rules inside our perception. Neat huh.

Re:Richard P. Feynman said...

[Llywelyn]

My roommate's boyfriend at college (no, neither she nor he come to /.) was describing his QM book to me: evidently, in the first few chapters they try to explain things in terms of physical concepts that he could understand.

Then, about three chapters in, the book makes something explicit: From here on out, don't try to understand it, just trust the mathematics :-)

Re:Richard P. Feynman said...

[3141]

If we can never truly perceive a thing in itself by sensing it, then why would perceiving it through text, maths and theory be any harder? Wouldn't it be easier since there is only pure logic to get your head around?

Re:Richard P. Feynman said...

[DrLudicrous]

Einstein didn't have a problem with the discreteness of quantum mechanics. As a matter of fact, any halfway decent mathematician (physicists included) would disagree with this property- it is the result of systems that are represented with certain differential equations PLUS boundary conditions which limit the solutions to said equations. These types of systems and equations have existed for over a hundred years longer than quantum mechanics.

What Einstein disagreed with were things like the Uncertainty Principle, the EPR paradox (If he had lived to see it), and most likely even Schrodinger's Cat. He disagreed with the assumptions that led to these conclusions. So Einstein was most definitely NOT a supporter of quantum mechanics as we now know it. Even the greatest can be mistaken.

Re:Richard P. Feynman said...

[DrLudicrous]

Sounds most definitely like the undergrad textbook by David Griffiths. Excellent text- chapter 3 is in the introduction of formalism.

Basically, formalism in quantum mechanics is expressing quantum mechanical ideas in the language of QM, namely linear algebra. Operators and observables (physical quantities like position, velocity, etc.) are represented either by matrices or " notation". This allows one to delve further into quantum mechanics, and allows one to use mathematics to predict phenomenon. In a sense, this complication of the mathematics for simple problems (like the hydrogen atom) allows one to do more complex problems (like the hydrogen atom in a magnetic field, where the energy levels of the orbitals will split).

So today, quantum is taught by trying to relate basic concepts in QM to those in classical mechanics (such as postition, energy, momentum, etc.) in the first few chapters in a book. Then to faciliate communicating QM ideas, formalism is introduced. It's like no one wants to write three plus two equals five, when 3+2=5 will suffice. This allows more difficult problems to be tackled more easily.

Re:Richard P. Feynman said...

[grahamlee]

What Einstein disagreed with were things like the Uncertainty Principle, the EPR paradox (If he had lived to see it), and most likely even Schrodinger's Cat[1]. He disagreed with the assumptions that led to these conclusions.

I think his main problem was the idea of Universal instantaneous collapse of the wavefunction (which leads to "spooky action at a distance"[2] and God playing "dice with the Universe"). These concepts came from the Copenhagen Interpretation, and was the best way the Quantum theoreticians could think to explain the seemingly counterintuitive results of QM - it's pure philosophy and has nothing to do with the Physics.

Of course not everyone necessarily subscribes Copenhagen now. My personal favourite explanation is the proposition popular in the 80s and in Sliders - that multiple Universes are created at each instant multiple outcomes are possible, each reflecting the different outcomes.

So Einstein was most definitely NOT a supporter of quantum mechanics as we now know it.

Quantum mechanics as we currently know it includes Bose-Einstein statistics describing the behaviour of systems of integer-spin particles (which leads to the concept of a Bose-Einstein condensate - a highly active area of research today); Light Amplification by Stimulated Emission of Radiation (described at the atomic scale by the Einstein coefficients); quantisation of electromagnetic radiation (proposed by Einstein); Einstein's explanation of the photoelectric effect (for which he received the Nobel prize). Stretching the boundaries a little, there are equations for the equilibrium number of charge carriers in Solid State physics which rely on the quantisation of charge in the material. These are known as the Einstein equations.

Even the greatest can be mistaken.

Such as when he removed lambda from his equation on the state of the Universe (his "biggest blunder", indeed :-)).

[1]Point of order: even Schroedinger didn't believe in Schroedinger's Cat. He set it up as a thought experiment to show how absurd QM is (I mean, who could really believe in a dead/alive cat? Not him). The experiment has of course, since been done, sans cat.

[2]He believed that the "instantaneous" collapse of the wavefunction would lead to information being propagated instantaneously throughout the Universe. Of course, the wavefunction is not a measurable quantity so this does not occur.

Re:Richard P. Feynman said...

[Anonymous Coward]

EPR paradox?

Isn't Einstein the "E" in the paradox? So he must have lived to see ot as he is one of the "inventors" of the paradox.

Or did I misunderstand you?

Re:Richard P. Feynman said...

[Anonymous Coward]

No, he (and the others) said, more or less, "if quantum mechanics is true, this weird thing would happen, which no one could possibly believe in". The problem is that many years later, when it became possible to run the experiment, the weird thing did, in fact, happen.

Re:Richard P. Feynman said...

[Anonymous Coward]

I have an enormous amount of respect for Feynman, because his formulation of quantum mechanics that makes my job a lot easier. However, I have to regards this statement as empty retoric and/or false humility. Understanding quantum mechanics is not more difficult then understanding classical mechanics. When you write both in the Hamilton formalism, the difference is not that big. This statement arises from a false interpretation of the word "understand". If you mean by understanding that you want to know why the mathematics looks the way it does, I agree, but by that definition, nobody understands classical mechanics either. Why does action equal and opposite reaction? Because assuming it does explains the world around us. Do I "understand" why? No, I just got used to the fact. Do I "understand" the consequences? Yes, using Newton's equations, I can accurately predict an awful lot of stuff going on in the world.

I the same sense, I do not "understand" why the world would obey something as counterintuitive as quantum mechanics. On the other hand, I can see the close mathematical analogy to classical mechanics (which we have all accepted), so it is not hard to imagine that this might actually work. Using the postulates of quantum mechanics, I can then calculate a huge amount of new stuff that I did not understand before I learned quantum mechanics.

I think my conclusion is that there is no such thing as understanding exactly why nature follows a certain set of rules. It's just that experiments lead us to believe that the mathematical formalism gives us something that looks like the reality around us. And besides devine intervention, that's the only thing we can ask from our theories. Clinging to the believe that understanding should be more than that is what religion is all about, but it has little to do with science.

Re:Richard P. Feynman said...

[Anonymous Coward]

Why should quantum mechanics be more incomprehensible then classical mechanics. You got used to classical mechanics and you therefore have the false sense of comprehension, but really your understanding of it is based on acceptense and experience. If you work with quantum mechanics long enough you learn to accept it in the same way and therefore understand it in the same way. The people who were doing physics when quantum mechanics was young had every right to complain, because the theory was basically a chaotic mess. However it has been formalized since then and the analogy to classical mechanics is much more evident. Furthermore, the thought experiments that people invented to show that quantum mechanics was unphysical have been performed and this "unphysical" behaviour is present in nature (Bell inequalities, violated by Alain Aspect and recently, Bose condensates have been used to create Schrodinger Kat states).

So, in conclusion, could you explain, without Kantian rhetoric, why quantum mechanics is inherently incomprehensible and classical mechanics is not?

Re:Richard P. Feynman said...

[DrLudicrous]

Agreed. I guess that what I was trying to get across is that he disagreed with the philosophy of quantum mechanics. Though B-E statistics, the laser, the photoelectric effect, etc., all fall out from the differential equations and the boundary conditions which lead to discreteness.

As an aside, have you had a chance to read the 1916 paper he wrote, which in the middle treats the laser phenomenon? Everyone references it, but I wonder how many have actually read it (see the other thread). It is very hard to come across, and I spent about a year looking for an English translation (On the Quantum Theory of Light [electromagnetism?])... very frustrating. Not even the world-class library at Bell Labs had a translation, though they did have the original german manuscript...

Re:Richard P. Feynman said...

[Anonymous Coward]

I don't think it's all that excellent. Too informal and doesn't emphasize the operator approach throughout (ex. calculating the eigenfunctions of the harmonic oscillator using an analytic expansion). Better would have been to the creation/annihilation operators on the ground state, and then put the series stuff into an appendix on the method of frobenius more generally. Shankar and Liboff are better, IMO.

Re:Richard P. Feynman said...

[grahamlee]

Everything I know about Optics I read in Hecht. I'm still at the stage (3rd year u/grad) where everything I need to know can come from textbooks (assuming, of course, that the textbook authors have read their references properly :-). Papers I've read have mainly been out of interest to find out what's currently being discussed, although I did read the SR paper in my first year. It's interesting, and surprisingly readable.

Re:Richard P. Feynman said...

[glwillia]

Oh god no, you don't want just Liboff to learn QM with. That is, unless your lecturer is really good--ours is decent, but the class is at 8 AM so it's a moot point--I'm currently in Quantum Theory II, the highest undergrad QM class at U of Arizona, and the text is Liboff. I, and several others, bought Griffiths on our own to get a good general understanding of what's going on, and then refer back to Liboff to look for the quantitative bits that are absent from Liboff.

All are better than Goswami, though.

BTW, with reference to this article, if you know math up through differential equations and want to learn about QM, I highly recommend Griffiths' book. It's not a reference text like Liboff, but it contains more than enough math so that it's not handwavy.

Re:Richard P. Feynman said...

[Anonymous Coward]

My friend, you did an excellent job in saying absolutely nothing

Re:Richard P. Feynman said...

[dragonsister]

What Einstein disagreed with were things like the Uncertainty Principle, the EPR paradox (If he had lived to see it),

You're telling me Einstein did not live to see the Einstein-Podolsky-Rosen paradox? The original paper was published in 1935 and a quick google tells me Einstein died in 1955 ...

Rachel
Nuclear Physics PhD student

Re:Richard P. Feynman said...

[DrLudicrous]

Shankar is too formal for most undergraduates. I like to use it as a reference for my grad classes. Quantum is not really learned at the undergrad level, just the basic concepts and a little bit of the formalism is introduced. IMHO, quantum mechanics is only grasped after tackling it at the graduate level.

Re:Richard P. Feynman said...

[anthony_dipierro]

I think his main problem was the idea of Universal instantaneous collapse of the wavefunction (which leads to "spooky action at a distance"[2] and God playing "dice with the Universe"). These concepts came from the Copenhagen Interpretation, and was the best way the Quantum theoreticians could think to explain the seemingly counterintuitive results of QM - it's pure philosophy and has nothing to do with the Physics.

Of course not everyone necessarily subscribes Copenhagen now. My personal favourite explanation is the proposition popular in the 80s and in Sliders - that multiple Universes are created at each instant multiple outcomes are possible, each reflecting the different outcomes.

I think you're confusing two different phenomena here. The Copenhagen Interpretation is more about explaining the wave-particle duality observations. In a two-slit experiment it can be proven conclusively that some aspect of a photon travels down both slits simultaneously. This can be explained best by a wave. But in the photoelectric effect there is a cutoff wavelength before the number of electrons emitted is proportional to the intensity of light. Thus (and you should read the details cause it's nonobvious from what I've said), photons must be quantised, as well as localised (this is clear if you send one photon at a time down a double slit experiment.

So how can light (and later we find all matter) be both a particle and a wave? Well, the Copenhagen Interpretation says that it's a quantized wave. Thus, it travels as a wave, then collapses to a single point upon interation with any other measurable property. This interpretation properly explains all current experimental results, but it has philosophical problems in that it violates the principle of locality, the principle that something in one place can't instantaneously affect something in another place.

The multiple worlds theory does not explain this paradox. Still, Einstein's theory, that there are hidden variables contained within the wave itself, has not been disproven completely. Bell's theorem, in answer to the EPR paradox, only disproves certain simple hidden variables theories.

At this point now I'm out of my league of expertise, so I'll defer to someone who's taken more than QM I.

Re:Richard P. Feynman said...

[grahamlee]

I was indeed talking about two separate things, however it appears that I was not clear in distinguishing them. I shall try and separate the two a little.

The Copenhagen interpretation does not say that matter is a localised wave. It says that matter is described by a wavefunction that extends over the whole Universe. It further says that when a measurement is made on some property of the wavefunction (e.g. the momentum, which is the first derivative of the wavefunction) then it must be found that the wave funtion is an eigenfunction of that property's operator. If the wavefunction previously was not, then it is said to "collapse" into one.
Einstein did not like the Copenhagen interpretation because it allowed for "spooky action at a distance" and various apparent paradoces.

When I pointed this out, someone replied to say that Einstein was not what we would think of as a Quantum Mechanic. I supplied evidence of multiple instances in modern QM where the groundwork was done by Einstein, including Bose-Einstein statistics, BECs, the photoelectric effect and others. The photoelectric effect is important because it was the first theory to give credibility to Planck's quantisation of the EM field.

I did not relate the photoelectric effect to Copenhagen. Oh and BTW your comment "in the photoelectric effect there is a cutoff wavelength before the number of electrons emitted is proportional to the intensity of light" is misleading. Properly there is a cutoff frequency given by, in meta-LaTeX, $h\nu_{min}=\Phi$, where $\Phi$ is the work function of the metal. It is an important distinction because the frequency of a photon with given energy is a constant, whereas the wavelength is variable and depends upon the refractive index of the medium.

Apologies if you thought that I was connecting the photoelectric effect with the Copenhagen interpretation. Of course any good philosophical interpretation of QM will be Physics-independent and yield correct answers for any problem. And the problem that Einstein had about non-locality is moot - here's a thought experiment for you, I hope it's explained succinctly enough - my degree doesn't have a very large written component!.

Imagine a source that emits two photons at a time, in opposite directions. We know that they must be oppositely polarised, so if I can set the polarisation of the photons you can measure them and I can send you a binary message, can't I?

We try it. I stand two light years away from the source in the -x direction with a Polaroid, you stand with a similar polaroid two light years away in the +x direction, and a detector one meter further away along the same axis. Now you keep your polaroid oriented so that it only transmits photons polarised with the z axis, I can choose whether to set mine along the z or y axes. So if I set a photon polarised y, you will see a photon in your detector. If I set a photon polarised along z, you will not. One and zero. We have a data transmitter. Or do we?

No. Because the photons that are emitted by the source are initially randomly polarised (or unpolarised, if you like). So whichever orientation I place my polaroid in, statistically we should expect 50% of the photons to be transmitted. No matter what I do, you will always see a random 50% of the photons in your detector. There is no useful information transmitted, and relativity is preserved.

Re:Richard P. Feynman said...

[anthony_dipierro]

OK, I agree with all that you said, including that I properly should have said frequency rather than wavelength. But your comment about Einstein's non-locality being moot I don't think is quite right.

Imagine a source that emits two photons at a time, in opposite directions. We know that they must be oppositely polarised, so if I can set the polarisation of the photons you can measure them and I can send you a binary message, can't I?

Sure, but this is easily explained by a hidden variables theory. One photon was always polarized one way, the other was always polarized the opposite way.

The current QM theory says that both photons were initially polarized both ways. Then when the measurement was taken the photons instantaneously collapsed into opposite polarizations. This is a much different interpretation, at least philosophically.

There is no useful information transmitted, and relativity is preserved.

Einstein's problem with non-locality was not just that relativity could be destroyed, it went to a fundamental belief about the universe. Perhaps it would be incorrect, but it should only be thrown out if there were absolutely no other way to justify experimental results.

Does Bell's theorem put us in that position? I have a couple more years of studying before I can even have an opinion on that one.

Maybe

[Anonymous Coward]

we just thought it happened in 1900 maybe it really happened in 1902 and a time traveler went back and changed history, but micheal retained memories of the previous timeline

Enrico Fermi Institute - Dec 2nd

[VoidEngineer]

Gotta love quantum physics...

Check out the University of Chicago's Physics Department for all the information you could want to know about modern research in quantum physics.

Oh, and December 2, 2002 was the 60th Anniversy of the first self-sustaining controlled release of nuclear energy

Re:Enrico Fermi Institute - Dec 2nd

[Anonymous Coward]

While the University of Chicago's Physics Department web page, there are a couple images that had captions of "exotic textures" and "whitespace." I mistook "whitespace" for a new physics phenonemon :P

Re:1900 + 100 = ?

[ramzak2k]

Maybe I'm just sleepy, but wasn't the anniversary two years ago?

Yes it was, they were a bit slow with it, but its finally here - the slashdot repost.

Presents!

[long_john_stewart_mi]

So I guess this calls for many discretely wrapped packets as a celebration? We could do that, or just flick the light switch a couple times... Yippeee! =)

Re:Presents!

[Anonymous Coward]

How is this offtopic? On anniversaries you usually receive gifts. 'Discrete packets' (quanta) were mentioned in the article. But, 'packets' can also be 'a small package or bundle' (which is where gifts come in). Please stop giving fucktards mod points, they hurt my karma.

Max Planck wasn't so smart..

[grub]

.. why didn't he use a computer instead of a chalkboard? That would have saved him a lot of time. But "Nooooo"; Mr. "Oh look at me, I'm Max 'Smarty Pants' Planck" played the waiting game like a run of the mill academic or government employee.

Re:Max Planck wasn't so smart..

[citog]

He wanted QM to be open source, which is why he developed it on a chalkboard. Other developers could simply 'rub out' parts of the code they didn't like and overwrite that area of storage. :-P

boo hoo

[coloth]

I didn't understand the impact of uncertainty until I saw The Crying Game.

Re:boo hoo

[Anonymous Coward]

THAT is a much better example of Schrodinger's cat! Brilliant!

You cannot know the sex of your courtship until you make the measurement, thereby collapsing the wavefunction onto one of the the two orthogonal eigenstates (in this case man and woman).

Re:Uncertainty

[Anonymous Coward]

did you calculate the leap years ?

My thoughts on the matter.

[Sean Johnson]

Of course describing energy as quanta is just a way for us to understand how things work. Anytime we discover and present a theory as to how things work in the universe we are presenting a picture or an incomplete slice of the whole (as how we understand it). Sure it helps us understand better, but we have to realize that it is not the way things work out per say (as a whole). Meandering on: A GUT theory is an admiral thing to strive for, but we must understand what it must take to come to such a comprehensive theory. All present theories will have to be thrown out of the window. They will never make cohesive integral sense incorporated into a GUT. Each time we delve further into quantumn particles we find more and more suprises. Likewise with peering into the vastness of space.
It is all so amazing and we must realize that any theories we come up with will never be able to describe things as a whole. It is basically the universe trying to understand itself...when it already knows. Dang....now I am getting into Zen philosophy so I will jsut shut up becasue I don't know where this is leading towards.

Re:My thoughts on the matter.

[Anonymous Coward]

"feel free to ignore me at all costs."

I will do just that ;)

Re:My thoughts on the matter.

[Sean Johnson]

I could had rambled on for paragraphs lining my thoughts out, but I ended it abrubtly because what's the point? And you have the audacity to simply ignore me just because my sig suggested that you do. Oh well ......who cares anyways!

Re:My thoughts on the matter.

[Anonymous Coward]

So, to summarize what you're saying,

"But what holds up that turtle?"

"But, dear Sir, it's turtles all the way down."

Re:My thoughts on the matter.

[samfreed]

And the degredation of "per se" (Latin) into "per say" (American English) is a demonstration of how the different "spins" of the USA and the rest of civilization cause different rates of degredation of language... Can this have anything to do with the degradation of maths (100 ?=? 102)?

This gives rise to the possibility that language (and math!) is radioactive. Duck!

Re:My thoughts on the matter.

[Sean Johnson]

Damn.. I will have to remember that "per se" thing. Thanks!

Re:My thoughts on the matter.

[teece]

We don't ever 'throw a theory out the window' in physics unless it was completely useless and silly to begin with.

Newton was, conceptually, completely wrong on some important points when he came up with his ideas of gravity. Did we throw his theory out the window when Einstein came up with Relativity? Heck no! Any useful scientific theory predicts something. Things like Newtonian physics are extremely useful, and to a large degree, correct at describing every day phenomenon. It was a requirement on the theory of relativity that it in some way incorporate, or reduce to, Newtonian physics.

Any GUT theory will have to do this. We won't really be throwing anything out the window, just adding to our knowledge. In same cases (eg Newton), even though the older theory is wrong, it is still very widely used because at the velocities, masses, and energies of every day life on earth, it is quite accurate.

If we find some way to replace QM, or incorporate gravity and QM, then relativity and the Shroedinger equation will both have to somehow be a part of the new theory, because the both accurately describe the universe.

Tim

Re:My thoughts on the matter.

[Sean Johnson]

Yes you are right. However, doesn't the principle of quantumn mechanics require some new form of thought structure that does NOT rely upon previously validated theories? Sure we may use the classic Newtonian theory structure in the partly formulating our Quantumn mechanical universe. But surely classical Newtonian physics alone did not allow us to manufacture semiconductors. It required a new train of thought. I was simply suggesting that a new train of thought needs to be entertained to adequately surmise a working Grand Unified Theory. By saying: "throwing other theories out the window", I meant that we need not rely upon previous schools of scientific thought per se. We need a radiclly new way of thinking about the universe. SOmething that has never been thought of before, or entertained from within any previous thoeries. A good example might be the superstring theory....although it still does rely upon other 'known' or "established' reservations about how the universe works, however unique it may seem.

Re:My thoughts on the matter.

[axxackall]

now I am getting into Zen philosophy so I will jsut shut up becasue I don't know where this is leading towards

For those of you who don't afraid of where this is leading towards, here are some interesting links between buddhism and fundamental phisics.

Quantum sunyata: Basically, what quantum theory says is that fundamental particles are empty of inherent existence and exist in an undefined state of potentialities. They have no inherent existence from their own side and do not become 'real' until a mind interacts with them and gives them meaning. Whenever and wherever there is no mind there is no meaning and no reality. This is a similar conclusion to the Mahayana Buddhist teachings on sunyata.

Sunyata - the emptiness of all things: It is important to emphasise that the mathematical equations of quantum physics do not describe actual existence - they describe potential for existence. Working out the equations of quantum mechanics for a system composed of fundamental particles produces a range of potential locations, values and attributes of the particles which evolve and change with time. But for any system only one of these potential states can become real, and - this is the revolutionary finding of quantum physics - what forces the range of the potentials to assume one value is the act of observation. Matter and energy are not in themselves phenomena, and do not become phenomena until they interact with the mind.

Buddhism copes with Science: "If there is any religion that would cope with modern scientific needs it would be Buddhism." -- Albert Einstein

A cosmic religion: "The religion of the future will be a cosmic religion. It should transcend a personal God and avoid dogmas and theology. Covering both the natural and the spiritual, it should be based on a religious sense arising from the experience of all things, natural and spiritual, as a meaningful unity. Buddhism answers this description." --- Albert Einstein

About buddhism: "Buddhism has the characteristics of what would be expected in the cosmic religion for the future: It trancends a personal God, avoids dogma and theology; it covers both the natural and the spiritual, and it is based on a religious sense aspiring from the experience of all things, natural and spiritual, as a meaningful unity." --- Albert Einstein.

My favorite quote of Albert Einstein: "Imagination is more important than knowledge".

Re:My thoughts on the matter.

[Anonymous Coward]

I am sorry but this view that nothing exists until it is observed is the type of horseshit we have to thank the Copenhagen Interpretation for.

Very few top-rank physicists 'believe' the Copenhagen Interpretation these days. I recall seeing a stat the other day (might have been on Slashdot) that 58% of physicists now accept the Many Worlds hypothesis as being the best current explanation of how the universe works.

In MWI, there is no need to posit a collapse of the wavefunction by an act of observation, because all eventualities can occur (and are actually played out, although with varying degrees of probablility).

Re:My thoughts on the matter.

[Anonymous Coward]

How does trite, obvious, content-free drivel like this get modded up as Insightful? Jesus H. Fuck.

Re:My thoughts on the matter.

[Alphtoo]

The Nature of the Universe is fun to play with. Expect no more, and you will be richly rewarded.

Sorry about the spelling...

[VoidEngineer]

Since I goofed on the last post, I'll add the obligatory links to:

CERN
The Enrico Fermi Institute
Fermi National Accelerator Laboratories
Agronne National Laboratories
Los Alamos National Laboratories

Yep, all the information you could want on modern Quantum Physics.

Re:Sorry about the spelling...

[Anonymous Coward]

That is, if you think that all modern quantum physics is done in high energy physics, which is certainly not the case, although they do receive by far the largest budget.

Re:Sorry about the spelling...

[VoidEngineer]

Agreed, which is why I included the link to the Enrico Fermi Institute... Materials, medical physics, imaging, cosmology and so forth are done there now. Used to work at the EFI, so I would know.

I absolutely agreed that it is not the case that all modern quantum physics is done in high energy physics. Alot of collaboration tends to happen at these locations, however, which drives the entire field forward differently than at other places.

Better than Slashdot grammar / spelling

[Leeji]

At least we can figure out how the hell they came up with it.

Since i'm not smart enough to make a joke here

[IIRCAFAIKIANAL]

Happy Birthday Quantum Physics! :)

Re:Since i'm not smart enough to make a joke here

[IIRCAFAIKIANAL]

Oh, and this is funny too.

Re:Since i'm not smart enough to make a joke here

[Anonymous Coward]

you forgot this one Attempts to reconcile Quantum physics with Relativity [angryflower.com];)

Re:Since i'm not smart enough to make a joke here

[grannyknot]

Call me old-fashioned, but you can't beat The Onion (or a reprint thereof).

Well, I knew most of the stories here were dusty..

[Anonymous Coward]

...as of late. But TWO YEARS? come on guys, your inbox can't be THAT backlogged? Can it?

Umm, oh wait.... This Is Slashdot(tm)!

Quantum Mechanically Speaking,

[eigerface]

There is a finite probability that this will be modded up to 5.

Re:Quantum Mechanically Speaking,

[Ignorant Aardvark]

> There is a finite probability that this will be modded up to 5. Yes, the modding up to 5 did happen, but I wonder what was the probability of it quantum tunneling into the state "Funny"?

Re:Quantum Mechanically Speaking,

[Swaffs]

There's a greater probability that you'll be labelled a karma whore.

Re:Quantum Mechanically Speaking,

[jpaz]

There is a finite probability that this will be modded up to 5

...and an infinite improbability too!

Re:Quantum Mechanically Speaking,

[Breakfast Pants]

Probaly a lot greater than the probability of it happening to your lame ass post.

Re:Quantum Mechanically Speaking,

[Anonymous Coward]

Then there must be some uncertainty principle that has those two quantities in an inequality.

More interestingly, by posting this you (and I) have affected the outcome... maybe :)

Basis of all science

[mnmn]

Through the wave of all the 2002-1900=100 jokes here, I would like to salute Mankinds greatest discovery, Qauntum Physics. This shows teh flexibility of the human brain, able to work with 4 dimensions (Relativity) to now (26 dimensions), and even something as strange as Quantum Mechanics, that defies our imagination and relies purely on reasoning, yet so powerful, it gave us the best of the last century's inventions, including the device you're staring at.

Quantum Mechanics is more than the kind of Physics that allows engineers to make locomotives. Its even more than what allowed us to land on the moon. As a warmer, we get nukes and the mighty computer. This physics promises us glimpses of the time the Universe was born, the quantum computer, time travel, teleportation, and many other things we have'nt imagined yet.

Physics has always been the foundation of knowledge, and it was replaced 100 years ago (+- 2 years). I think we're in for much bigger surprises this century.

Re:Basis of all science

[the gnat]

I would like to salute Mankinds greatest discovery, Qauntum Physics. This shows teh flexibility of the human brain

Sounds like your brain is a little too flexible right now. Go home and sleep it off, dude.

Re:Basis of all science

[BCoates]

Quantum Mechanics is more than the kind of Physics that allows engineers to make locomotives. Its even more than what allowed us to land on the moon. As a warmer, we get nukes and the mighty computer. This physics promises us glimpses of the time the Universe was born, the quantum computer, time travel, teleportation, and many other things we have'nt imagined yet.

Naah, once we get SDI working and perfect Genetics, it's just Future Tech 1, Future Tech 2... for as long as we keep bothering with science spending.

--
Benjamin Coates

Re:Basis of all science

[Anonymous Coward]

Although I think some of your glimpses are a bit far fetched, I do basically agree with you on the power of quantum mechanics and your celebration of the human intelect. I also have to add that if you work with quantum mechanics long enough (a few years is all it takes), it grows on you. In a sense, you began to develope an intuition in the same way we have an (often incorrect) intuition about classical physics. This makes it a lot easier to do the math.

Re:Basis of all science

[Frodo2002]

Grr, the human brain can only handle three dimensions. String theory got rid of 26 dimensions years ago with super symmetry (now down to 10 or 11). The triumph of the human mind is to be able to invent ways of dealing with a number of dimensions which is beyond conception and to do it successfully.

Re:Basis of all science

[spectatorion]

As a warmer, we get nukes and the mighty computer.

Actually, nuclear weapons are a result of the other great physical theoretical advance of the twentieth century, relativity (E = mc^2 and all that). Sorry to be picky, but let's give credit where credit is due.

Re:Basis of all science

[mnmn]

I never let it get into Future tech 1.. just swithc science to 0% and tax to 100% and start building battleships in all cities, or else the spaceship.

Re:Basis of all science

[mnmn]

Exactly what I meant by 'flexible' brain. Instead of sitting in a quite place and trying to imagine a flashlight firing photons while travelling at c, we come up with Hilbert Space equations, power up the pirated Mathematica and just work with the numbers. Only AFTER we get a working mathematical description, do we try to decipher the meaning of the thing and see if theres a new science there. The fact that we have'nt pinned down Quantum Mechanics in our heads means we're onto something big, thats already been proven in the last 100 years, but we STILL dont get Quantum Physics, and more surprises are coming.

Re:Basis of all science

[mnmn]

Maybe I'm naiive, but I remember introductory text on Quantum Mechanics, both by John Gribbin and Feynman tells you NOT to try imagine the going ons in for instance, the double-slit experiment. Working with the math alone is the key to Quantum Mechanics, or at least NOT letting your 3d imagination butt-in and spoil the calculations. Perhaps thats what you mean by 'develop an intuition'.

Re:Basis of all science

[mnmn]

The long process of building nukes doesnt rely on Relativistic equations alone. At the least, simulating the molecules and sub-atomic particles, and other statistical equations lend themselves to the equations by Schroedinger, Heisenburg and the long line that follows.

Definitions

[tgrotvedt]

Nine times out of ten, when people speak of quanta, they really mean photons. Photons are a typr of quanta, and by far the most understood type in science today. Photons are the quanta that make up the energy we see in light, and can detect along many of the frequencies of electromagnetic radiation.

When Planck was studying spectra, he was mostly dealing with photons, and then layed down the fundamental parts of quantum theory, outlining the physics behind these "digital" packages, which Einstein later defined as photons.

Re:Definitions

[Anonymous Coward]

Photons are definitely not the most understood quanta. The photons that Einstein postulate were nothing more than resonant chunks of electromagnetic radiation, i.e., they are semiclassical entities that you get when you quantize the motion of electrons around a nucleus, but not the electromagnetic field. The em-field itself is continuous, but the electrons just have a very curious taste and only eat certain chunk of light.

The "real" photons are the particles that you get when you really quantize the em-field as well. This is the theory called Quantum Electrodynamics. These photons are excitations of the light field. With this I mean, that in the absense of light, you still have the light field, it's just an empty field. To make a photon with a certain wavelength, you just excite that mode in the light field, in the same way you would excite a standing wave on a guitar string by picking it.

As you can see, to understand photons, you have to know Quantum Electrodynamics. Although I work on an everyday basis with quantum mechanics, I do not in fact know how to use Quantum Electrodynamics (because outside of high energy physics, there's not much use for it). Which means that I do not understand the details about photons. At the risk of sounding arrogant, I would say that if a publishing theoretical quantum physicist doesn't understand photons, they can hardly be called "the most understood".

Ofcourse in the Einstein language of photons, I agree with you. They are very boring quanta *grin*.

p.s. Crediting Planck for laying down the fundamental parts of quantum theory is historically incorrect. Planck didn't understand quantization in the modern sense of the word and did not even realize the his mathematical trick might have fundamental consequences. He has always been a thermodynamic kind of guy and should be appreciated for his work in that field.

Re:Definitions

[Anonymous Coward]

Bullshit. If you're actually a "publishing theoretical quantum physicist," you can do QED in your sleep. WTF are you doing anyway? Whether you're doing loop quantum gravity, post-SM phenomemonlogy, or string theory, you can do field theory.

Ok, Slow news day. Other cool Dec 14th events:

[Leeji]

this page talks about some other interesting scientific events that have their anniversary today:

1986 - First non-stop, non-refuelled flight around the world
1967 - Announcement of first synthesis of biologically active DNA
1962 - Mariner transmits information from first-ever rendezvous with Venus

Re:Belief in a God is stupid

[Sean Johnson]

It could also be argued that science is used to control people...or capitalism for that matter. It all boils down to one things....human nature. There is a place for science and a place for religion, and they are on each one side of the coin. The thing we have to do is see the coin as a whole. It is best to realize that science AND religion are cohesive and not neccessarily "against" or "opposite" eachother Thus one may achieve harmony with both the knowable and the unknowable.

Argh this is all B.S.!

[Ignorant Aardvark]

Are you certain it's the 100th anniversary? No, because of Heisenberg's Uncertainty Principle ... well, can you at least give me a probability that it is the 100th anniversary? Personally, I'm putting my money on it being the 102th anniversary, but that's just me.

Re:Argh this is all B.S.!

[Anonymous Coward]

Heisenberg's Uncertainty Principle deals with measuring the position of an object in spacetime. Measuring the passage of time is entirely different - we will never know the exact position of a quark but we can determine exactly how long it has been since the discovery of quarks.

Re:Argh this is all B.S.!

[Old Wolf]

the one hundred and tooth anniversary?

Incisive comment... my money is on it being the 102nd :) (which in fact it is, as this page reveals).

But in Russia there is no word for...

[Quirk]

...discrete... indiscrete packets? Would Schrodenger's cat be let out of the bag?

Re:Belief in a God is stupid

[Anonymous Coward]

well maybe this balance both does and does not exist, and maybe will or won't ever. (Ouch my head hurts)

Wasn't it Boltzmann

[GMOL]

I've read that the notion of quanta first came about from Boltzmann's statisical mechanics, with the notion of entropy coming in discrete units....

Re:Wasn't it Boltzmann

[daniel_mcl]

As I recall, the "discrete units" for Boltzman were atoms, which nobody believed in at the time. Quanta are units of energy.

Re:Falsity of Quantum Mechanics

[Anonymous Coward]

The modding of this post proves my point

Re:RPN

[Anonymous Coward]

So then, in RPN, how do you calculate 2002 - 1900 = 102?

Re:Belief in a God is stupid

[Sean Johnson]

That is reminiscent of the ten gates of being or awreness ( I freakin' forgot) purported in certain Zen sects. Both knowing and not knowing, but at the same time not both of those, and also YES both of of those, but not neither of of those, and also definately either of the aforementioned possibilities. If you study Zen enough, I assure you, your brain will hurt as it never has before.

Re:Bah

[infernow]

Isn't it only fitting that there be uncertainty surrounding the origins of Quantum Physics?

Quantum Physics -- entanglement

[Alan Holman]

I read a thing about entanglement; that's a quantum-physics thingy when one particle is "entangled" with another particle; it means that the two particles are exactly the same; they're a pair which do the exact same things at the exact same times, and it doesn't even matter how far apart they are in the universe; they'll always do the same things at the same times no matter where they are in the universe. One could be on mars, and a person could drain two electrons from it, and its partner could be on pluto with two electrons jumping from it. Yes, you can manipulate these particles and their manipulations would be copied wherever else they are in the entire universe -- isn't this freaky stuff? Ever since hearing this entanglement thing, which isn't a theory THERE'S PROOF!!! Anyhoo, once I heard about this, it started me thinking about communications applications, and soforth. Ever heard of an ansible? If you have, you're gasping now at the possibility of such things actually existing, all thanks to entanglement. For those who don't know, an ansible is an instantanious communication device which can be used anywhere in the universe; it's currently just a theory, but thanks to quantum entanglement of particles, it's more possible. See, entangled particles come in pairs. One could be on earth, and the other could be on Catland, which is the planet in the center of the universe. Someone makes the one on earth cause an atomic blast, and the one on Catland will cause an atomic blast -- faster than lightspeed travel because it's not actually faster than lightspeed travel because the pair of particles are the same thing! Trippy, ain't it? It's quantum physics. Quantum Physics is cool! Happy birthday Quantum physics! (Banana Chan, which wasn't mentioned here, is at http://www.geocities.com/radiomovie2002/ )

Re:Quantum Physics -- entanglement

[Jason1729]

An entangled particle is subatomic. That means it doesn't have electrons to drain away.

What do you think you mean by manipulate the particles?

The only thing entagled particles share is spin. If you move one particle the other does not also move.

The Heisenberg Uncertainty Principle still applies, so that it is possible for a particle to travel faster than light, but it is not possible to send a signal faster than light. The proof by contridiction for that under quantum theory is still quite simple.

How does one use a single subatomic particle to "cause" a nuclear blast? The statement is meaningless.

Most of the people here have read the Ender series and know what an ansible is. A science fiction story does not equal a quantum mechanics theory.

Jason

Re:Quantum Physics -- entanglement

[Anonymous Coward]

As I remember, you are correct about the particles only having spin. But I also remember that it is possible to change the spin on said particle, thereby changing the spin of the entagled particle. Since you can have up and down spins, you could create a binary communication device, although I have no idea if you can entangle sub-atomic particles on purpose, or if it's just that each particle is entangled with some other particle some where. Any ideas?

Re:Quantum Physics -- entanglement

[Anonymous Coward]

It might be possilbe to use entanglement to send information by using spin states, but until they solve the issue of seeing the states without changing them, much the same issue with quantum computing

Re:Quantum Physics -- entanglement

[Absurd Being]

Unfortunately, can't be easily used to make an ansible. You'd need several times more energy than the universe has to entangle the wavefunctions of the particles over such a distance.

Re:Quantum Physics -- entanglement

[Anonymous Coward]

The only thing entagled particles share is spin. If you move one particle the other does not also move.

entangled particles can, whilst entangled, share any anti-symmetric eigenstate basis. not just spin.

Re:Quantum Physics -- entanglement

[fridzappa]

Yes, you can show that entanglement acts over arbitrary distances instantaneously[!!] (it doesn't take much energy, either). Somehow, particles can conspire through means surpassing the speed of light (or so it seems to us mere mortals); there is even a simple undergraduate experiment on the subject...however, things work out such that we cannot use this to our advantage; we're stuck with speed-of-light communication for the forseeable future.

Re:Quantum Physics -- entanglement

[Anonymous Coward]

1.) Entanglement has more to do with determining the state of a particle and then knowing more about the partner particle than you "should" be able to know than it does with two things "doing the same things" at the same time. After all, you're presuming that they do not go in the same direction...

2.) A "proven" theory is still a theory. Newton's theory of gravitation, Einstein's theory of gravitation, Theory of Quantum Energy. Theory of Evolution. Theory is ultimate in science.

A Theory in Science is something totally different from what the average person thinks is a theory. What an average person thinks of when he/she hears the word "Theory" is really closer to what scientists would call an "Hypothesis".

See the definitions at:
http://dictionary.reference.com/search?q=theo ry
The first definition fits science; the last fits the general population.

JD

Re:Quantum Physics -- entanglement

[etcshadow]

Wow... I don't even know where to start...

"it doesn't even matter how far apart they are in the universe; they'll always do the same things at the same times no matter where they are in the universe"

Wrong wrong wrong wrong wrong. Quantum entanglement says that the two particles *started off the same (or opposite or some such relationship of the initial states). It follows, then that if you do not *observe* either particle for quite some time, and take the two of them far distant from one another, then the instant that you *observe* the state of one particle, you immediately *know* the state of the other particle (wherever it is).

This gives at first pass the illusion that you have gotten information at faster than the speed of light... I mean, you did just *instantaneously* learn the state of a particle far, far away, right? That's gotta mean that you communcated with that thing way over there, right? No. Not at all.

Now, what makes this interesting is the fact that quantum mechanics tells us that if you don't *observe* either particle's state, then neither particle has actually "picked" a state yet. So, it's as though the one particle *told* the other one that "hey I was observed at state A, so you must now occupy state B". So, now it appears that information has traveled faster than the speed of light... and I won't argue that point, because last I knew better scientists than me were still duking that one out.

However, one thing that anyone with a basic understanding of this can agree upon is the fact that there is no way to *use* the possible information transfer involved in the collapse of a wave function to TRANSMIT INFORMATION. Why? Well, there is no way to observe a wave function directly. You can only measure some operator on a wave function (like energy, position, spin), and by doing so, you collapse the wave function into an eigenfunction of that operator. However there is no way to tell whether the eigenfunction you observe is the result of *your* observation or someone elses. In other words, you can't tell if you collapsed the wave function or if someone else did, and quantum entanglement doesn't *do* anything other than pre-collapse the wave-fcuntion for you.

Re:Quantum Physics -- entanglement

[etcshadow]

"As I remember, you are correct about the particles only having spin. But I also remember that it is possible to change the spin on said particle, thereby changing the spin of the entagled particle"

No, that's not what entanglement means. Entanglement means that you have two particles occupying states which have some relationship to one another, but you don't know which state either one is in... yet. However, because of the relationship between the two particles states, you know that if you observe one, you immediately know the others state, wherever it is. However, if you change the state of one particle or the other, you break the entanglement.

Also, if you want an example of entanglement occuring naturally, here is one: two anti-particles (such as an electron and positron) anihilate one another, and release the energy as photons (you gotta have two photons to uphold conservation of momentum). Let's say that the positron and electron had opposite spins, so the total spin of the system was zero. Now, for conservation of momentum, the two photons created must have opposite spin from one another. Of course, you don't know for either particular one whether it is spin up down or zero... al you know is that if it is spin up, the other is down; if it is down the other is up, and if it is zero, so is the other.

(For anyone too anal to see that I rattled this off quickly, please forgive any minor errors... like, I don't know off the top of my head if there some restriction in the example above that you can't get two spin-zero photons out of this mess... and I know that I oversimplified things a bit)

Re:Quantum Physics -- entanglement

[Jason1729]

You can't entangle particles over a distance. Entangled particles are created at the same time and place, they can then be transported apart.

Amount of energy isn't an issue.

Wavefunctions don't entangle. A wave function is just the probability of a certain particle being in a certain state at a certain time.

Jason

Re:Quantum Physics -- entanglement

[Anonymous Coward]

Besides spin along the axes, what other anti-symmetric eigenstates can an entangled particle have?

Re:Quantum Physics -- entanglement

[Anonymous Coward]

Entanglement is not limited to subatomic particles. In recent experiments, Rubidium atoms in physically seperate containers have been entangled using laser light.

Furthermore, entanglement is not limited to spin. In fact, the original EPR proposel was by intangling the motion of two particles.

Third, the Heisenberg principle has nothing to do with the fact that FTL communication is not possible. The reason is that you have to send a clasical bit for each quantum state that you want to teleport, so it is always slower then light. Mind you, these experiments are being done in many groups around the world. They might not be useful for long range communication, but the teleportation of a quantum state by moving a clasical bit, makes the requirements for a quantum computing much less strict.

Re:Quantum Physics -- entanglement

[totierne]

I was going to spout off here, the entagled post of me saying something useful is even now hitting the next galaxy. By reading this the entangled posts probability wave function has collapsed to a score 5, while this posts has collapsed to a -1.

I do not see entanglement increasing my karma in this universe.

Re:Quantum Physics -- entanglement

[Alan Holman]

Your post made me realise that the article I read about entanglement sucked. And then I posted the same wrong information to slashdot without knowing how wrong the information was.

Re:Quantum Physics -- entanglement

[Anonymous Coward]

You can only measure some operator on a wave function (like energy, position, spin), and by doing so, you collapse the wave function into an eigenfunction of that operator.

In Soviet Russia, WAVE FUNCTION COLLAPSES ON YOU!

Re:Quantum Physics -- entanglement

[Anonymous Coward]

> Now, what makes this interesting is the fact that quantum mechanics tells us that if you don't *observe* either particle's state, then neither particle has actually "picked" a state yet.

Not true. Under MWI, the particle takes all possible states. Which state you observe depends on which universe 'you' are in - there is no privileged reference frame, no collapse of the wavefunction.

No need for this Copenhagenqsque 'observer-observed' nonsense.

Re:Quantum Physics -- entanglement

[Associate]

Great idea Allan. BTW, do you play the drums? I'm starting a band call Iron Butterfly. How's your dad?

Re:Quantum Physics -- entanglement

[Anonymous Coward]

"Wrong wrong wrong wrong wrong. Quantum entanglement says that the two particles *started off the same (or opposite or some such relationship of the initial states). It follows, then that if you do not *observe* either particle for quite some time, and take the two of them far distant from one another, then the instant that you *observe* the state of one particle, you immediately *know* the state of the other particle (wherever it is)."

Funny how people trying to explain this phenomenon automatically say something wrong. Actually the part of your answer I quoted contains several errors:

- "the two particles" this is the most common error. There are no "two particles". There is a single "system".

- "*observe* and *know*", that is restated afterwards. The non-separability problem is definitely not a problem of knowledge of the state of the two particles. Before the observation, there exist no such particles, so talking about their state is uncorrect. Saying the observation gives the knowledge of the state they had before the measurement is uncorrect. Even saying that their state is undefined before is uncorrect.

There exist a system which is defined by some probalistic function (density of probability). This system can range over large distances. When a measure is done on this system, the system is transformed into two particles, individual, separated by a large distance. And the measurement returns the state of the particle with respect to the measured quantity.

Please! please! please! There exist no such thing as two individual particles (correlated or anti-correlated) before the measurement. It is a pure nonsense to talk about their state before the measurement.

Re:RPN

[Anonymous Coward]

You give the calculator to cmdrTaco.

Just in case

[drmofe]

In case the Slashdot editor's inboxes get too clogged up, I'd just like to note that 2003 is the 100th anniversary of flight. Maybe someone can post the story now so that it makes it to the front page in time.

Of course, here in New Zealand, we celebrate the anniversary somewhat earlier than you do in the US :-)

STF

Re:Just in case

[Tablizer]

In case the Slashdot editor's inboxes get too clogged up, I'd just like to note that 2003 is the 100th anniversary of flight. Maybe someone can post the story now so that it makes it to the front page in time.

Too many dead cats clogging their quantum inbox.

BTW, Wanna hear a joke about the Heisengberg Roach Hotel?

If only...

[Stalyn]

Quantum Physics was president we wouldn't have the problems we have today...

Re:RPN

[Anonymous Coward]

And if you want 2002 - 1900 = 100?

Tomble answers your questions!

[Tomble]

Maybe I'm just sleepy, but wasn't the anniversary two years ago?

Well, reader, that's certainly an easy mistake to make, considering the title of the story, but if you look a little more carefully at the body, it becomes clear that the title (perhaps chosen by someone else) was wrong and inaccurate in a very different way, probably only badly chosen, due to a simple misunderstanding of the facts:

On December 14, 1900, Max Planck presented experimental results in front of the German Physical Society and announced that they could best be explained if energy exists in discrete packets, which he called "quanta". Today is the 100th birthday of Quantum Physics

As you can doubtless see from a second look, it all fits into place that Planck's announcement, which lead to other scientists further investigating the full ramifications of the theory, was the conception of Quantum Physics as we know and love it today. Whilst the title is obviously innacurate, the observation that today is Quantum Physics' 100th birthday is clearly correct, as it is broadly accepted that models of reality have a 2 year gestation period- a similar duration to elephants, I believe.

Sadly, though, Quantum Physics has not been too lucky in love, having had occasional brief flings with 50's icon Relativity, whom everyone would have liked to see it matched up with, but it never quite seemed to work out for them- it seems they just had too many differences.

Although we all wish Quantum Physics well, and it seems surely impossible that such a great catch would never get married (who knows, maybe good old Q.P will be able to patch things up with Relativity after all), it shall obviously not be having any anniversaries for some time yet.

Hope this clears everything up,
Tomble

Re:Tomble answers your questions!

[Anonymous Coward]

To try so hard... and fail so well.

Reverse Polish Notation

[Anonymous Coward]

2002
1900
-

God bless this man

[SteweyGriffin]

Max Planck. Two words, one name. Leader of modern physics. Inventor. Courageous. Man of all worlds, man of all nations, lover of physics, worshipper of love and all that is good and worldly. Planck was a genius, but didn't claim to be one. Yet, he invented something in his lab that parallels the importance of Einstein, Feynman, and Wright's findings -- quantum physics! The interactions of small little particles. Here is some more information: World>Deutsch>Wissenschaft>Forschungseinrichtungen

Max-Planck-Gesellschaft - [ Translate this page ]
Max-Planck-Institute betreiben Grundlagenforschung in den Natur-, Bio-
und Geisteswissenschaften im Dienste der Allgemeinheit. Insbesondere ...
Description: Übersicht aller Institute in Deutschland.
Category: World>Deutsch>Wissenschaft>Forschungseinrichtungen
www.mpg.de/ - 20k - Dec. 13, 2002 - Cached - Similar pages

Max Planck Society
... Max Planck Research 3/2002 Cover, The new issue of the MaxPlanckResearch
magazine has been released. ... Recommendations of the Max Planck Society. ...
Description: Max Planck Institutes carry on basic research in service to the general public in the areas of natural...
Category: Science>Institutions>ResearchInstitutes
www.mpg.de/english/ - 17k - Dec. 13, 2002 - Cached - Similar pages
[ More results from www.mpg.de ]

MPIfM
MAX PLANCK INSTITUTE OF MATHEMATICS MAX-PLANCK-INSTITUT FÜR MATHEMATIK
Vivatsgasse ... Max Planck Society for the Advancement of Science Max ...
www.mpim-bonn.mpg.de/static/home.html - 8k - Cached - Similar pages

Max-Planck-Institut für Informatik: Home Page
... International Max Planck Research School for Computer Science (IMPRS) PhD Programme
and fellowships for graduates of all nationalities European Union Marie ...
Description: Saarbrücken (Deutschland)
Category: World>Deutsch>...>Informatik>Forschungseinrichtung en
www.mpi-sb.mpg.de/ - 9k - Dec. 13, 2002 - Cached - Similar pages

Max-Planck-Institut fuer Astrophysik, Garching - [ Translate this page ]
Description: Prominent research institution in astrophysics.
Category: Science>Physics>Astrophysics>Institutions
www.mpa-garching.mpg.de/ - 1k - Cached - Similar pages

Planck
... Max Planck came from an academic family, his father being professor of law at
Kiel and both his grandfather and great-grandfather had been professors of ...
www-gap.dcs.st-and.ac.uk/~history/ Mathematicians/Planck.html - 12k - Cached - Similar pages

Max Planck Institute for Psycholinguistics, Nijmegen - Home
... The Max Planck Institute for Psycholinguistics is one of the institutes of the
German Max-Planck-Gesellschaft zur Förderung der Wissenschaften eV Currently ...
www.mpi.nl/world/ - 5k - Cached - Similar pages

Max-Planck-Institut für Gesellschaftsforschung - Homepage - [ Translate this page ]
... The Max Planck Institute for the Study of Societies is an institute
for advanced research in the social sciences. It builds a bridge ...
Description: Köln (Deutschland)
Category: World>Deutsch>...>Forschungseinrichtungen
www.mpi-fg-koeln.mpg.de/ - 21k - Dec. 13, 2002 - Cached - Similar pages

Max-Planck-Institut für Plasmaphysik - [ Translate this page ]
Das Max-Planck-Institut für Plasmaphysik untersucht die physikalischen Grundlagen
für ein Fusionskraftwerk, das - ähnlich wie die Sonne - Energie aus der ...
Description: Garching (Deutschland)
Category: World>Deutsch>...>Physik>Forschungseinrichtunge n
www.ipp.mpg.de/ - 14k - Dec. 13, 2002 - Cached - Similar pages

Max Planck Institut fuer Radioastronomie Bonn - [ Translate this page ]
[english]. Aktuell, Das Institut. Forschung, Mitarbeiter.
Öffentlichkeit, Intranet. webmaster@mpifr-bonn.mpg.de.
Description: Bonn (Deutschland)
Category: World>Deutsch>...>Astronomie>Forschungseinrichtung en
www.mpifr-bonn.mpg.de/ - 2k - Cached - Similar pages

Re:God bless this man

[darkov]

I dub this post, any the increasing number like it, the Google Troll. The shocking thing is that they get modded up... but I guess that is the point of trolling.

Re:God bless this man

[guybarr]

Yet, he invented something in his lab that parallels the importance of Einstein, Feynman, and Wright's findings -- quantum physics!

even back then, it was not one-genius alone.
Science is a social phenomena. Heroe-worship is not a bad thing in itself,
just remember that those heroes were a part of someting greater than a single human.

Be it Saint Albert (E), Isaac (N), Karl (G) or Max (P), they were part of the "church", and the credit falls to many others as well.

Public Advisory

[pyth]

Our teams of scientists have discovered that this article contains trace references to Quantum Mechanics.
As such, there is a risk of discussions developing that involve people talking out of their
completely uninformed ass. Some of the most common symptoms of Quantum Ass-Talking Syndrome (QATS) involve the following topics:

• Philosophy - free will, determinism, subjectivity
  
• Theology - god's omni-something, predestination, free will [again]
  
• Science - failure of predictability
  

If you feel the urge to discuss these topics, we advise that you immediately consult somebody who knows what the hell they're talking about. If further trouble develops, a dose of reality is recommended.

Re:Public Advisory

[po8]

That was cool! My thanks for attempting to ease the frequent pain experienced by those of us who have taken even a single undergraduate QM course, as a result of the spread of QATS among our friends and associates.

QATS is a strange disease; it inverts the normal parasite-host relationship by causing pain only in those exposed who are not susceptible.

Hopefully we will someday find a cure for QATS among the vector population. Failing that, I guess we can pinpoint their energy level so precisely that they disappear, or someth-Oh no! I've been infected! Someone please help me!!...

Re:Public Advisory

[Tablizer]

Our teams of scientists have discovered that this article contains trace references to Quantum Mechanics. As such, there is a risk of discussions developing that involve people talking out of their completely uninformed ass. Some of the most common symptoms of Quantum Ass-Talking Syndrome

But F-ing with sci cliches and buzzwords is such good practice for IT consulting. Stop raining on my training.

Re:Public Advisory

[guybarr]

QATS is a strange disease; it inverts the normal parasite-host relationship by causing pain only in those exposed who are not susceptible

The term "Physics Karaoke" springs to mind.

Re:Public Advisory

[Idarubicin]

The term "Physics Karaoke" springs to mind.

Absolutely. It is generally accepted at my university that the physicists are the worst singers in the Faculty of Science. In my experience, biochemists generally are the most talented by far.

Re:Public Advisory

[Frodo2002]

[rant]Here here. And I recommend the immediate censorship of all popular science authors and their books. And just to stir trouble, I mean not only Chopra (duh), but Hawking, Kaku, the whole crowd of them. They all add to the spread of the evil QATS virus. [/rant]

Re:RPN

[Anonymous Coward]

you give the calculator to michael instead.

Speaking of Michael, he should be fired from slashdot because of his part in the censorware project.

I have a gut theory......

[sawilson]

I think I incorporated too many cohesive integral
slices of pizza in my gut. It's a fairly
comprehensive theory, with tangible links to the
Grand Lack of Excersize theory. But seriously....

My feeling is that we try to look way too far ahead
instead of just saying "we don't know". It amazes
me that we'll occasionally overlook something so
incredibly useful like the "tornado in a can" but
have the nerve to propose increasingly bizarre shit
based on a foundation of bizarre shit. I'm sure
that if we live long enough, we'll get our Grand
Unification, and that it's probably our purpose
for existing in the first place. I'm just an
advocate for not blatantly charging forward and
basing new things on old things that aren't much
better than voodoo. It's ok to say "We don't
really know".

In NETHACK

[Genyin]

we EAT quantum mechanics.

in soviet russia

[Anonymous Coward]

YOU smell government 10km away!

In Soviet Russia.... quantum tunnels you!

[danratherfan]

Well god bless. the development of quantum mechanics has allowed mankind a look into how strange the universe can really be.

As Hawking said (to paraphrase)... not only does God play dice but some times he throws them where no one can see.

One of the things i find so funny about it is how much physicist seem to hate it, even the ones that helped found it!

However it is the most accurate theory in modern physics, which is why it has become known as the standard model.Perhaps string theory or M-theory can help make it a bit more astetic... which seems to be what most physicist go for these days.

Re:Ok, Slow news day. Other cool Dec 14th events:

[Anonymous Coward]

> 1986 - First non-stop, non-refuelled flight around
> the world

Woohoo! 15th anniversary!

/. submission queue

[dfay]

Wow, I guess that means that this is the 2-year anniversary of that story being first submitted to /. I'm glad to see it finally made it on to the front page. Congrats, EricR. :)

Oh, please...

[Anonymous Coward]

...a quick cut-and-paste from agnostica.com makes the front page?!

Meh.

The Question!

[Ianworld]

The question is though: Did it exist before we found out it existed?

Sorry, all this talk of RPN means I NEED this...

[Tomble]

In SOVIET POLAND,
Notation reverses YOU!

Whereas of course,
In SOVIET RUSSIA,
RPN POLISHES you!

Although strictly speaking, that probably should have been:

In SOVIET POLAND,
Notation YOU! reverses

Whilst SOVIET RUSSIA has it's own method of doing these things, which didn't quite catch on in the west.

Sorry about that, everyone.

What Planck actually discovered

[CactusCritter]

The wavelength distribution of blackbody radiation had been determined some (many?) years earlier. However, no one could figure out how to to explain how it could come about.

Somehow, Planck worked out an equation which yielded that wavelength distribution quite precisely. I believe that it is correct that his model was a "what if" conjecture about energy exisiting in discrete packets.

As discussed, the rest is history.

53 years of passing time has dimmed my memory, but I'm pretty sure that is the story.

Re:What Planck actually discovered

[Anonymous Coward]

wavelength distribution, while approximatedearlier than planck, wasn't known exactly. They just had some function(s) that fit the known data (ie, corrected the rayleigh-jeans ultraviolet catastrophe).

Plank showed, by solving statistically-mechanically, a series of independent discrete quanta(estimating the photon oscillation as simple-harmonic), the allowed spectrum was consistent with the observed data.

Lucky for him, simple harmonic oscillators have that exact energy spectra (E=hbar*omega(N+1/2)) where N is the energy-level (or quantum number) of the oscillator. Lucky guess, or insight of pure genious. No other (that i know of) systems have such an energy spectra (evenly-spaced, singly occupied). simple examples are particle-in-box and hydrogen atom.

This method of the blackbody radiation as quantum simple-harmonic oscillators is also very nearly similar to calculating the specific heat of crystals (Einstein method for independent oscillators, but corrected by Debye for coupled oscillators up to a sharp cutoff frequency).

This, though, ushered in new tidings, not just for pure quantum physics, but for statistical physics of quantum objects (bosons, fermions) which have different statistical distributions than classical particles (maxwell-boltzmann statistics). paved the way for solid-state physics to burgeon forth (hello transistors!!!)

Re:What Planck actually discovered

[Frodo2002]

What happened with Planck (roughly as I know it) is as follows:

1. People had already suggested the idea of sub-microscopic oscillators as a possible method of explaining what was going on.
2. Planck deliberately decided to sit down and see if he could reproduce the power distribution given empirically by Wien's law using the idea of a statistical ensemble of sub-microscopic oscillators.
3. Boltzmann had figured a computational technique whereby you assumed a discrete set of energy levels in a statistical ensemble and then took the continuum limit at the end.
4. Planck, after some months of trying discovered that he could reproduce Wien's law if he followed Boltzmann's computational technique, (taking the continuum limit) but stopped at the scale given by the constant of proportionality h ie: Planck's constant.
5. He then decided to give this a straight up physical interpretation that the oscillators were themselves stable (in violation of maxwellian electrodynamics --- something which disturbed him quite deeply I think) and emitted their radiation in discrete energy steps - integral numbers of hf where f is the frequency of the oscillator.

That as I understand is what Planck did. After he spoke about it, he spend a lot of time apologising for the interpretation which he disliked and spend a lot of time trying to find a way to get back to a picture which was consistent with classical electrodynamics. Eventually he himself admitted defeat and accepted his own interpretation.

Re:What Planck actually discovered

[CactusCritter]

Thanks, Anonymous Coward. (I don't know, of course, if you are the same Anonymous Coward whom I already thanked for the exposition about David Bohm.) My undergraduate education didn't get into the Planck's derivation as deeply as yours did and I am pleased sot have leaned about it.

Re:Quantum mechanics allright

[AresTheImpaler]

By the same phenomenon that will post this article late and then be moderated Redundant

viva mexico!

Yep

[Anonymous Coward]

It's a quantum thing. If you don't understand how 1900 - 2002 is 100 years, you need to go back to physics class. Schroedinger's cat would understand.

Happy Agnostica!

[brandonY]

Everybody get out your Schroedinger boxes out!

I think it can be

[Anonymous Coward]

But then again when you try to show that it is understood you can not communicate this. As that is a problem with smart people.

Irwin Schroedinger said...

[Anonymous Coward]

I don't like it [quantum mechanics], and I'm sorry I ever had anything to do with it. [Upon the realization that his attempt to disprove the whole quantum jumping thing had, instead, proved it. Yes, boys and girls, those damnedable Schroedinger wave formulas you struggled with were the unfortunate result of poor Irwin's efforts to discredit the fledgling quantum theory.]

A koan:

[Ayanami Rei]

If you study Zen enough, I assure you, your brain will hurt as it never has before.

And then, you will understand that pain is only a temporal effect, and it will cease to seem displeasant.
And the pain will be gone, suddenly. ^_^

Schroedinger's cat is DEAD

[algernon7]

Last time I checked, anyway...

Re:Schroedinger's cat is DEAD

[Anonymous Coward]

LOL!

the best tribute would be...

[Anonymous Coward]

if dumb ass sales people could quit useing "quantum leap" meaning large leap. Quantum means tiny, bitch!

Re:the best tribute would be...

[Anonymous Coward]

i guess these sales drones just live light years in the future.

You Sir, Are An IDIOT

[Ayanami Rei]

. I'm just an
advocate for not blatantly charging forward and
basing new things on old things that aren't much
better than voodoo. It's ok to say "We don't
really know".


Ummm... Mr.-Most-Important-Person-in-the-World, just because YOU don't understand it doesn't make it invalid, or useless. Without quantum physics (which IS incidentally the topic of discussion), you wouldn't have transistors and their elk, culminating in the computer with which you posted this backwoods tin-foil-hat-wearing drivel.

The tornado-in-a-can doesn't look too impressive compared to a 1/4 inch square chip that can simulate the folding of protein, or powers a Korg Triton.

An academic in his free time using a computer figured out why the shower curtain in a shower gets sucked in with a few days of his spare time. The guy who invented the tornado in a can took 15 years of on/off effort.

That is why we have academics working in institutions on that wacky shit, because we want to put the stuff it into practice ASAP.

You can't tell me you don't want warp drive, because that would be frickin' cool. We gotta slog through the simple stuff (GUT) before we can start bending the rules... :)

first official freek-out recorded?

[Tablizer]

He showed that a cathode ray firing one electron at a time still produces an interference pattern. That means that though the electrons are fired discretely, there is a wave pattern formed perfectly alike to interference patterns. So the electron either knows where past electrons went and future electrons will go, and governs itself accordingly, or there are rules that apply to the things outside our perception which are contrary to the rules inside our perception. Neat huh.

That kind of stuff is just plain freeky. It is more "logical" to try to assume that the partical *did* take all possible paths and interfered with each of these possibilities, but our universe only "sees" one of these possibilities. IOW, light really is a wave, but we see only one "strand" (partical) of it in our universe. That I can more or less relate to, dispite still being weird. It is just a matter of a filtered view of the whole, like a WHERE clause in SQL. But if that is not the explanation, then I am clueless to try to comprehend such weirdness.

BTW, who is the *first* researcher to notice the weirdness of QP? IOW, the first to say something like, "This is really getting creepy" rather than just a clinical view of "this is kind of curious". Einstein called it "spooky action", but was he the first?

Re:first official freek-out recorded?

[MulluskO]

I don't buy that one, really. I'm inclined to think that the photon emitting device, siply because it is not at absolute zero, cannot be perfectly still, I think it must vibrate in a way that a photon might notice. The results, in my opinion, are best described by chaos theory, and I think that in most circumstances it provides a more rational decription of our world than quantum theory.

Re:first official freek-out recorded?

[cameldrv]

Light can be treated as a wave under many many circumstances. Lots of everyday devices rely on this. Yet, we have the photoelectric effect, also used in many everyday devices. In the single photon emitter case, how does the emitter know that there are two slits, or the geometry of the slits, etc? You might want to do a bit more reading, as something as simple as chaos just doesn't account for this type of effect.

Re:first official freek-out recorded?

[noshellswill]

I understand that the photo-electric effect is not all that easy to truly quantitate. The PHOTON explanation of why intense but long(er)-wavelength radiation will not eject an electron has never seemed NECESSARY to me.

Re:first official freek-out recorded?

[MulluskO]

Well, as a certainty, whether a photon is regarded as a particle or a wave it is interacting in some way with the slits, that is, the slits are changing the light's trajectory. I contend that the slits' interaction with the light is altered and determined by the lights position relative to the slits as it passes them. The lens, light source, and all other components of the photon-emitting apparatus are certainly moving, enough to make a difference in the trajectory of the photon as it passes the slit. I think this is much more feasible than the idea of multiple universes for explaining how light can continue to behave as a wave in situations in which only one photon is involved.

Re:first official freek-out recorded?

[Anonymous Coward]

You might want to do a bit more reading,

Maybe if you are an atheist all you really need to do is a bit more reading of the bible.

Re:first official freek-out recorded?

[Anonymous Coward]

It depends what you call spooky. Einsteins idea of spookiness was formalized in the Einstein Podolsky Rosen thought experiment, where you keep two particles in a joint superposition, which makes it possible to influence the state of one particles instantaniously by measuring the state of the other particles, even if it's lightyears away. This behaviour (also refered to as the violation of Bell Inequalites) was first measured by Alain Aspect.

Re:first official freek-out recorded?

[yomegaman]

Look, go calculate how a single-photon double-slit apparatus can produce an intereference pattern without using QM, then I'll believe you. This nattering about 'chaos' is just hot air otherwise. How can it be more 'feasible' than QM, when QM perfectly describes the observed behavior and your 'theory' hasn't been shown to do so?

Re:first official freek-out recorded?

[sconeu]

In the single photon emitter case, how does the emitter know that there are two slits, or the geometry of the slits, etc?

Cramer came up with an explanation, the Transactional Interpretation. Gribbin gives a reasonably good explanation of it in "Schroedinger's Kittens".

Re:first official freek-out recorded?

[cameldrv]

Well, it's a bit difficult to even imagine this given that the quantized nature of the atom is intimately connected with the quantized nature of light. Given this, suppose I had a very intense but long wavelength source, and pointed it at some atoms. We would expect that the due to the ammount of power, it would impart energy to the electrons in the atoms, as it does with short wavelengths. However, this doesn't happen. So the question is why, and QM explains this by saying that the electrons have discrete energy levels, and that to kick them up an energy level, you need to hit them with a photon with at least as much energy as the difference. This essentally says that kicking up an energy level is a discrete event, and either you have enough energy or you don't. If we use the pure wave formulation, with enough power, you should be able to impart enough energy on the atom to cause this to happen, but it doesn't work.

Perhaps you already knew all of this. I am not a physicist, but hopefully this helps.

Birthday Party

[hermescom]

At Quantum Physics' 100th birthday party, a number of notable personalities were on hand.

Republican Majority Leader, Trent Lott, made a birthday speech congratulating Quantum Physics with its 100 year anniversary, and fondly recalled when during the planning stages of the Manhattan project, scientists were considering building a weapon of mass destruction based on Quantum Physical principles.

"I can tell you now, I wish they'd picked Quantum Physics," Lott said, "If they did, I'm sure the world as we know it would be a better place for white people to live."

Face it: The Universe is just plain Fscked

[Tablizer]

It might be possilbe to use entanglement to send [instantaneous] information by using spin states, but until they solve the issue of seeing the states without changing them, much the same issue with quantum computing

God is teasing us. We cannot have our cake and eat it too. QP is just like this all over. If I was religious, I just might interpret this as a big Neener Neener Neener from the beyond. It is the biggest sign of a Teasing God since the discovery that zits appear mostly on the body parts most visible to the public. Does the act of observing a face cause zits? Nobel in there for somebody.

Relativity and Quantum Mechanics

[Teflik]

Paul Dirac wed Relativity and Quantum Mechanics long ago. It's where we get the proof of spin and anti-particles.

Re:Relativity and Quantum Mechanics

[Tomble]

It is? Oh OK. I think I must have been thinking more of the Quantum Gravity thing. Is it just the general theory of relativity that deals with gravity? Or am I getting my wires horribly crossed?

And is that proof of anti-particles that you mention, because relativity allows things going faster than light to go back in time? What I think I'd dimly understood from Feynman was that anti-particles were fundamentally the same as their normal-matter equivalents, but travelling the opposite way in time, such that when they collided (or were spontaneously generated), it was actually just one particle sort of "bouncing" in the temporal dimension, with an associated transfer of energy one way or the other. Have I got that right?

I certainly have no idea about how it affects spin, as I've never quite got what exactly spin meant other than it seems to "classify" particles quite significantly. I would be intrigued to hear some sort of explanation about what spin actually meant.

Re:Relativity and Quantum Mechanics

[Teflik]

Unfortunately, I don't know the details of relativity+QM -- It's something that my QM professor mentioned (stuff that we'd learn when we got to graduate level QM).

Spin is something of a misnomer. What it is is the magnetic moment of a particle. Imagine the electron having a magnetic "north pole" and "south pole". The weird thing is, even neutrons have spin (ie, they have a north pole and a south pole). (It turns out that this is because neutrons are made up of charged quarks.)

People figured out that electrons and atoms have magnetic moments (ie, spin) because of how they behaved when passing through non-uniform magnetic fields.

Spin (magnetic moments at the quantum level) is weird. Some days I think I've got it, then I learn a little bit more, then I think I don't got it. (I guess it's because QM is weird, then so is spin...) Classically, you could imagine "spin up" as an electron with it's north pole pointing up, and "spin down" as the north pole pointing down. In QM, you get linear combinations of states, and it's really just the probability that you find it in one state or another. Not only that, but if you measure the spin on a different (orthogonal) axis (say you wanted to measure if it was "spin left" or "spin right") then that would effect what you were doing on your up-down axis.

Christmas Break: I don't have to do any Quantum Physics for a month!

And he hated it

[teece]

Whats ironic is that Boltzmann first came up with this idea, and Planck was one of his primary detractors. Boltzmann, despondent that nobody found his description of a probabilistic interpretation of things interesting, killed himself.

Not long after, Planck came forward using Boltzmann's ideas. There is some evidence to show that Planck's true hope was that he would be proved wrong -- he didn't like the quanta or probability interpretation at all.

Tim

Want a pacifier?

[sawilson]

Ummm... Mr.-Most-Important-Person-in-the-World, just because YOU don't understand it doesn't make it invalid, or useless.

How incredibly blind or drunk are you to take my
words and turn them into me calling anything invalid
or useless? What makes you think I don't understand
quantum physics? Having a bad day? Need some midol?

Without quantum physics (which IS incidentally the topic of discussion), you wouldn't have transistors and their elk, culminating in the computer with which you posted this backwoods tin-foil-hat-wearing drivel.

NO KIDDING!! exactly what part of my problem with
bullshit science that seems to have to reinvent
itself every 50 years because OOPS! WE MISSED
SUMPIN! BUT WE GOT IT THIS TIME HONEST!!! don't
you understand?

The tornado-in-a-can doesn't look too impressive compared to a 1/4 inch square chip that can simulate the folding of protein, or powers a Korg Triton.

That's a matter of perspective. Imagine, if you
CAN, an advanced vortex based processor with
perfectly timed speed, pressure, and velocity to
keep 1 billion particles in motion, and powered
by static charge, while each particle retains a
trackable id of some sort, and can rapidly change
between 10 different states enabling a fast
efficient base 10 computational platform. You
invent the wheel before you invent the space
shuttle. Don't be so narrow in your thinking.

An academic in his free time using a computer figured out why the shower curtain in a shower gets sucked in with a few days of his spare time. The guy who invented the tornado in a can took 15 years of on/off effort.

You don't have to player hate. You don't have to
feel so threatened because someone outside the
comfort of academia did something nobody else
can understand. It happens all the time. There
isn't one true way to learn or do anything.

As for warp drive, sure. Why not. Why wouldn't I
want that. Hopefully we are mature enough at
that point that someone doesn't make it a weapon.
Chances are that weapon research will create the
first warp drive. You can't think of things as
"simple stuff" or "hard stuff". It's just stuff.
How you look at it. Pick a better target for your
childish flames next time you feel like stomping
your feet.

Mod that up (insightful)

[Anonymous Coward]

If ever there was an insightful bloke

Chunk physics

[Black Copter Control]

Back in the late '80s John Wheeler was at the University of Alberta. As luck would have it I was the Tech at the student Radio station who got to edit his interview. I remember two things from him. One was the quote he found in a bathroom:

Time is nature's way of keeping everything from happening all at once.

The other was his discription of the etymology of "quantum". Essentially it's just German for "unit" or "chunk". He figured that if Plank had been a native English speaker, we'd probably be dealing with "chunk" physics instead of "quantum" physics.
.. Just had to share that.

Re:Chunk physics

[exspecto]

chunk physics? you mean the fat kid in goonies? then i guess the physics would be some equation detailing the viscosity of a malt dripping down a large restaurant window?

Re:Chunk physics

[gwalla]

Quantum isn't German for chunk, it's Latin for amount.

The ansible?

[iq in binary]

Of course I've heard of it.

Any self respecting geek has heard of it.

Ever read Ender's Game by Orson Scott Card? Thought so. However he didn't refer to quantum mechanics, he referred to Philotics.

Look it up, Philotics is interesting stuff.

David Bohm - implicate-order hypothesis -

[Anonymous Coward]

Interview with David Bohm
http://www.fdavidpeat.com/interviews/bohm.ht m

David Bohm 1917-1992

In 1950 David Bohm wrote what many physicists consider to be a model textbook on quantum mechanics. Ironically, he has never accepted that theory of physics. In the history of science he is a maverick, a member of that small group of physicists-including Albert Einstein, Eugene Wigner, Erwin Schrödinger, Alfred Lande, Paul Dirac, and John Wheeler--who have expressed grave doubts that a theory founded on indeterminism and chance could give us a true view of the universe around us.

Today's generation of physicists, impressed by the stunning successes of quantum physics--from nuclear weapons to lasers-are of a different mind. They are busy applying quantum mechanics to areas its original creators never imagined. Stephen Hawking, for example, used it to describe the creation of elementary particles from black holes and to argue that the universe exploded into being in a quantum-mechanical event.

Bucking this tide of modern physics for more than 30 years, Bohm has been more than a gadfly. His objections to the foundations of quantum mechanics have gradually coalesced into an extension of the theory so sweeping that it amounts to a new view of reality. Believing that the nature of things is not reducible to fragments or particles, he argues for a holistic view of the universe. He demands that we learn to regard matter and life as a whole, coherent domain, which he calls the implicate order.

Most other physicists discard Bohm's logic without bothering to scrutinize it. Part of the difficulty is that his implicate order is rife with paradox. Another problem is the sheer range of his ideas, which encompass such hitherto nonphysical subjects as consciousness, society, truth, language, and the process of scientific theory making itself.

The son of a furniture dealer, Bohm was born in Wilkes-Barre, Pennsylvania, in 1917. He studied physics at the University of California with J. Robert Oppenheimer. Unwilling to testify against his former teacher and other friends during the McCarthy hearings, Bohm left the United States and took a post at the University of São Paulo, Brazil. From there he moved to Israel, then England, where he eventually became professor of physics at Birkbeck College in London.

Bohm is perhaps best known for his early work on the interactions of electrons in metals. He showed that their individual, haphazard movement concealed a highly organized and cooperative behavior called plasma oscillation. This intimation of an order underlying apparent chaos was pivotal in Bohm's development.

In 1959 Bohm, working with Yakir Ahronov, showed that a magnetic field might alter the behavior of electrons without touching them: If two electron beams were passed on either side of a space containing a magnetic field, the field would retard the waves of one beam even though it did not penetrate the space and actually touch the electrons. This 'AB effect" was verified a year later.

During the Fifties and Sixties Bohm expanded his belief in the existence of hidden variables that control seemingly random quantum events, and from that point on, his ideas diverged more and more from the mainstream of modern physics. His books Causality and Chance in Modern Physics and Wholeness and the Implicate Order, published in 1957 and 1980, respectively, spell out his new theory in considerable detail. In the Sixties Bohm met the Indian philosopher Jiddu Krishnamurti, and their continuing dialogues, published as a book, The Ending of Time, helped the physicist clarify his ideas about wholeness and order.

Recently retired from Birkbeck College, Bohm is now trying to develop a mathematical version of his implicate-order hypothesis-the kind of precise, testable theory that other physicists will take seriously. It is not an easy task, for Bohm's universe is a strange, mystical place in which past, present, and future coexist. The objects in his universe, even the subatomic particles, are secondary; it is a process of movement, continuous unfolding and enfolding from a seamless whole that is fundamental. To test the theory of general relativity, Einstein forecast that the sun's gravity would bend light waves from distant stars; he was correct. So far Bohm has been unable to find an experimental aspect that could support his ideas in the same way.

Although recently recovered from serious heart surgery, Bohm continues to make frequent trips throughout Europe and to the United States, where he lectures, talks to colleagues, and encourages students. His ideas have been enthusiastically received by philosophers, neuroscientists, theologians, poets, and artists.

Re:David Bohm - implicate-order hypothesis -

[CactusCritter]

Thanks, Anonymous Coward. Bohm's work, it seems, was emerging a bit just before I graduated from college with a B. Sc. in Physics. I found it fascinating, but doubt that I have the mental horspower left to comprehend it. But I am gratified to know that such deep thinking has been done and its approximate nature.

No.

[Anonymous Coward]

No, Schroedinger's cat is not dead. The poor cat is the worlds first qubit.

How many Schroedinger cats do we need to build a quantum computer??

Bell's Inequality

[donsaklad]

What is Bell's Inequality?...



Cheer and seasons greetings!
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Re:Bell's Inequality

[guybarr]

read Sakurai's book. It's in there.

Re:Bell's Inequality

[ice cream koan]

Here goes...

One of the odd phenomena observed in quantum mechanics is the creation of tandem photons from certain kinds of light sources that have the odd characteristic that their dynamic properties are very strongly correlated. That is, if two observers measure the polarization of one photon each, they will observe the same value for the polarization. Quantum mechanically speaking however, if, say, the two photons are polarized at some angle perpendicular to its line of travel, and you set up your measurement apparatus to measure the polarization at a different angle, then QM does not tell you what polarization value you will observe, but gives you a probability. The observed polarization for one photon is essentially random, but the distribution of values for many photons will follow the probability predicted.

Now several physicists, notably Einstein, took this bizarre feat of the correlated photons to mean that the polarization values for the two photons had to be dependent on some hidden variables that QM just didn't know about, but that became apparent in the experiment, which became known as the Einstein-Podalsky-Rosen (EPR) paradox.

Now, in the '60s, along came Bell, who was working on the EPR paradox hoping to prove Einstein et al correct. Bell's inequality reasons what the maximum possible correlation between the two photons should be, assuming that once the two are created, the one cannot affect the other. The problem is, the EPR paradox, when carried out in real experiments, has been shown to violate this inequality: the two photons are much more strongly correlated than they have any right to be according to a hidden-variables-locality-preserved interpretation of QM.

In the mathematical description of QM, this behavior has to do with the fact that in QM the two photons are not treated separately, but must be modelled by one function in hilbert space. The two photons are "phase entagled". Einstein particularly disliked this property of QM because it seems to throw out the principle of locality (no action-at-a-distance), although currently I believe the accepted idea is that no "information" can be sent non-locally using entaglement. I'll leave those questions to a real physicist.

See EPR Paradox

Re:Bell's Inequality

[Anonymous Coward]

Carefully.

Re:Signature of God? Probably not

[Anonymous Coward]

No IN SOVIET RUSSIA the idiot fucks you!!

The ability to perceive or think differently...

[kedi]

Quantum Physicist and Philosopher David Bohm, born in Pennsylvania in 1917 died in England in 1992, a contemporary of Einstein and a student of Openheimer, wrote what many physicists consider to be a model textbook on quantum mechanics in 1950.

According to this web site:
http://www.gurteen.com/gurteen/gurteen.nsf/ 0/26DAA D8A936EA8D680256816005EB1D6/
Bohm was also the founder of MITs DIALOGUE project, which somehow seems to be linked to or behind the OpenCourseware project.

"The ability to perceive or think differently is more important than the knowledge gained." David Bohm.

Excerpts from an interview with David Bohm:

Omni: Yet you've said that quantum mechanics doesn't provide a clear picture of nature. What do you mean?
Bohm: The main problem is that quantum mechanics gives only the probability of an experimental result. Neither the decay of an atomic nucleus nor the fact that it decays at one moment and not another can be properly pictured within the theory. It can only enable you to predict statistically the results of various experiments.

Physics has changed from its earlier form, when it tried to explain things and give some physical picture. Now the essence is regarded as mathematical. It's felt the truth is in the formulas. Now they may find an algorithm by which they hope to explain a wider range of experimental results, but it will still have inconsistencies. They hope that they can eventually explain all the results that could be gotten, but that is only a hope.

Omni: How did the founders of quantum mechanics initially receive your book Quantum Theory?
Bohm: In the Fifties, when I sent it around to various physicists-including [Niels] Bohr, Einstein, and [Wolfgangl Pauli--Bohr didn't answer, but Pauli liked it. Einstein sent me a message that he'd like to talk with me. When we met he said the book had done about as well as you could do with quantum mechanics. But he was still not convinced it was a satisfactory theory.

Bell's Inequality

[donsaklad]

How might Bell's Inequality be explained for a high school physics class?...

Ummm

[Anonymous Coward]

Me thinks you do not know of what you speak. You almost get there, but no, you miss.

Mod up please

[Anonymous Coward]

This is an insightful and *accurate* description of a tricky subject. Well done.

ps. I am theoretical physics PhD student.

100 years from now...

[Ektanoor]

Today we commemorate the 100 years since /. editors managed to successfully demonstrate that quantum leaps also occur in the macroworld...

I'm waiting....

[zozzi]

I'm waiting for someone to post a slashdot link indicating it's dupe post from 2 years ago...

Niels Bohr

[Anonymous Coward]

Niels Bohr once said
Anybody who is not shocked by quantum theory has not understood it
So the 2002 - 1900 = 100 effect has proven (once again) with its schocking effect the broad understanding of the subject amongst /.'ers. :-)

Funny!

[farrellj]

But remember to strip for the nurse!

ttyl
Farrell

Re:Uncertainty

[A Gremlin In Kremlin]

Or the quantum leap years?

If I read the article...

[Rams�s Morales]

...will it change?

Y2k Compliance

[LucianTheMad]

100 years after 1900 would, in RealMath, be 2000, I do Believe. Maybe the poster isn't Y2k compliant. Maybe he/she has been submitting this every year since 2000, and it was finaly posted. Or the Majority can't do math, which is a little dissettling.

Re:Y2k Compliance

[Jamesie]

What's wrong with 'unsettling'?

Re:Y2k Compliance

[Anonymous Coward]

I find Slashdot posters' lack of mathematical and grammatical skills to be most dissettling.

Don't hate me because I'm beautiful

[Anonymous Coward]

(and smarter than you fucking losers)

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* Reply to "Well duh" by johnrpenner Saturday December 14, @11:18PM
* Moderation of "Spielberg Over the Hill?" Saturday December 14, @11:30PM

GHZ

[donsaklad]

What's GHZ and how might GHZ be explained
for a high school physics class?...



oo__ don@saklad.org

Weblog Guide to Problematical Boston Public Library Use
http://GuideToProblematicalLibraryUse.WebLogs.com/ stories

Anyone selling mod points on eBay?

[BerntB]

There is a finite probability that this will be modded up to 5.

Hmm, not related, but -- I've wondered when this'll happen:
Any selling/buying of mod points on eBay?

To be able to fake word-of-mouth must be a dream for ad agencies. Say, "Insightful" +5 for messages that claim a commercial compiler give better code than another (and a few 'Trolls' on comments that disagree). No worse than ordering studies guaranteed to get a "correct" result, which of course not even Msoft would do...

(Exchange service? "You get as many mod points as you give up -- the browser plugin do the work". Not much worse than writing auto-aimers for games!)

I'm not even going to think about what good ad money an application reading can make... How many mod points a month could be generated? (Needs a few prepared messages to fake a real person.)

(N B: I haven't looked, but if a /.-user in any way can see who modded whom to what, it should probably be turned off... Could be used for an "exchange".)

To do some meta-modding here, if you mod this positive, vote "Funny" -- not "Interesting"! (-: Don't make me more cynical, please! :-)

Re:Anyone selling mod points on eBay?

[damiam]

Someone once tried to sell an account with lots of karma on eBay (this was before the karma cap). IIRC, Taco set the karma to slowly decrease until it reached zero at the end of the auction.

Wait another two years

[EmbeddedJanitor]

"it is broadly accepted that models of reality have a 2 year gestation period"

Yeah, well then maybe we should wait another two years until we're certain it is the 100th birthday.

Zen and physics

[pclminion]

It is all so amazing and we must realize that any theories we come up with will never be able to describe things as a whole. It is basically the universe trying to understand itself...when it already knows. Dang....now I am getting into Zen philosophy so I will jsut shut up becasue I don't know where this is leading towards.

Have you read Heisenberg's "Physics and Philosophy?"

The major problem people are having with QM, the reason this "Zen" thing keeps coming up, is that QM says something incredibly strange about the world: the results of any experiment or measurement are inextricably tied up with the very act of measurement. QM seems to shatter the idea that an objective universe exists independently of the observer.

What QM is trying to tell us is that there is no way to actually draw a line between observer and observed. That's why people always bring up Zen (or Buddhism in general), since one of its major philosophical principles is that the separation between self and universe is an illusion.

Re:Zen and physics

[Planesdragon]

The major problem people are having with QM, the reason this "Zen" thing keeps coming up, is that QM says something incredibly strange about the world: the results of any experiment or measurement are inextricably tied up with the very act of measurement. QM seems to shatter the idea that an objective universe exists independently of the observer.

I don't believe that it does. The universe got along quite well without us--there isn't, AFAIK, a standing theory that requires life for the universe to exist, like the Zen "it's all imaginary" line does.

The objective universe exists. But once we get to a fine enough scale, it's simply impossible to measure something without changing it. What's so counterintuitive about that?

What QM is trying to tell us is that there is no way to actually draw a line between observer and observed. That's why people always bring up Zen (or Buddhism in general), since one of its major philosophical principles is that the separation between self and universe is an illusion.

I think it's blowing a few simple artifacts of the creation of knowledge a bit out of proportion.

Pick up a book on the Kabbalah, if you want a religious parallell to QM that doesn't rely on personal revelation for the transmission of knowledge.

Re:Zen and physics

[pclminion]

I don't believe that it does. The universe got along quite well without us--there isn't, AFAIK, a standing theory that requires life for the universe to exist, like the Zen "it's all imaginary" line does.

Whoa, hold on. I never said (nor does Zen ever state) that the universe is "imaginary." That is meaningless bullshit, and people unfortunately often misinterpret Zen that way. What Zen (and all forms of Buddhism, really) states is that there is no objective universe. The universe does not exist independently of any observer or "object" within it. It is the dualism between observer and universe which is illusion. You've taken my original statement ("A and B are equivalent") and interpretted it as "A cannot exist without B." That doesn't follow logically.

The objective universe exists. But once we get to a fine enough scale, it's simply impossible to measure something without changing it. What's so counterintuitive about that?

Nothing, in a lot of cases. The classic example is trying to measure the temperature of a thimbleful of water with a thermometer -- by putting the thermometer in the thimble, you change the water's temperature. But Schrodinger's cat is both alive and dead, until I (the observer) look in the box. Are you saying that isn't counterintuitive? Or are you saying Schrodinger was wrong?

Re:Zen and physics

[Planesdragon]

You've taken my original statement ("A and B are equivalent") and interpretted it as "A cannot exist without B." That doesn't follow logically.

It's a grammatical problem. "B influences A" and "B is a subset of A", when uttered as profound statements, are easily inferred as "A does not exist without B."

I understand what you're saying. I just don't think most peole who blurr Zen and QM do.

Nothing, in a lot of cases. The classic example is trying to measure the temperature of a thimbleful of water with a thermometer -- by putting the thermometer in the thimble, you change the water's temperature. But Schrodinger's cat is both alive and dead, until I (the observer) look in the box. Are you saying that isn't counterintuitive? Or are you saying Schrodinger was wrong?

I think Schrodinger was wrong. Or rather, incomplete.

"Until we open the box and Learn if the cat is alive or dead, we must act & plan as if it were both alive and dead."

The cat is either alive or dead. However, until we determine which is which, we need to have a box to bury the cat in & enough food to feed the cat.

Re:Ok, Slow news day. Other cool Dec 14th events:

[INMCM]

Wow, Max Planck looks a lot Dr. Mind Bender from G.I. Joe. Makes you think.

A commentary....

[Anonymous Coward]

Entanglement....particle.....wave function.....BLAM

Ok, now for some rest.

Two year old news from Agnostica.com

[Nukees]

Heh heh, that really was ripped word for word from Agnostica.com, right down to the announcement of the "100th" anniversary. Of course, the funny thing is that that "news" item announced the launch of the Agnostica site, two years ago when it was the 100th year anniversary, for sure.

Guess I need to update the site more often.

Nice to know the folks at Slashdot celebrate Agnostica, though!

100th!

[Knacklappen]

And in related news:
"Scientist don't re-calculate the numbers they cite"
"156 fast CD-burners are equivalent to 421 normal ones"

Fuzzy numbers!

[Knacklappen]

Na, I think the calculation got messed up by using fuzzy numbers...Speaking of it, I feel a litte fuzzy myself...

can never find a good Quantum Mechanic

[peter303]

I can never find a good Quantum Mechanic when I need one. My qubits are entangled again and I need a tune up.

Re:Belief in a God is stupid

[Anonymous Coward]

Religon is used to control people, and the universe was never created, it has always been around, or will be explained someday as always repeating itself.

Theism is just stupid.

Give money to church, so your priest can continue raping young boys and not need a real job. Thank You :)