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?

[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?

[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?

[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?

[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?

[anthony_dipierro]

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

Richard P. Feynman said...

[bartash]

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

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...

[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...

[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]

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...

[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...

[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...

[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.

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

boo hoo

[coloth]

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

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.

[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.

[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".

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...

[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.

Quantum Mechanically Speaking,

[eigerface]

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

Re:Quantum Mechanically Speaking,

[Swaffs]

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

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

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.

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

But in Russia there is no word for...

[Quirk]

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

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

[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.

If only...

[Stalyn]

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

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

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

[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.

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.

/. 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. :)

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!!!)

Schroedinger's cat is DEAD

[algernon7]

Last time I checked, anyway...

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... :)

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.

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

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).

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.

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

[gwalla]

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

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.

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...

Funny!

[farrellj]

But remember to strip for the nurse!

ttyl
Farrell

If I read the article...

[Rams�s Morales]

...will it change?

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

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

[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.

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!

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".

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: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.