Physicists Seek Answers to Quantum Correlations

Aug 14, 2008 by Lisa Zyga weblog
Fiber Optics
Physicists sent two photons down optical fibers toward different destinations, and found that the photons could instantly sense each other´s behavior.

After performing multiple tests on two entangled photons, physicists have yet again found that the photons seem to be communicating faster than the speed of light - at least 100,000 times faster. The researchers hope that their results might encourage theorists to come up with new explanations for the strange quantum mechanical effect.

The physicists, led by Nicolas Gisin from the University of Geneva, arranged their experiment by sending two photons down fiber optic cables to detectors in two Swiss villages located 18 km apart. Both photons started in Geneva, with one heading toward Satigny and the other toward Jussy. The study, which is published in Nature, builds on previous tests published a few months ago in Physical Review Letters.

When the researchers measured several properties of each photon at its destination, they found that the particles could instantly sense the other´s behavior without any known communication. Although this correlation obeys the laws of quantum mechanics, it seems to defy the nature of space and time, at least from humans´ everyday perspectives.

The physicists ruled out several possible classical explanations for the instantaneous communication. For one thing, they showed that the photons did not share information before leaving Geneva, and so they didn´t travel knowing about each other´s properties.

In another test, the scientists showed that no communication could have occurred through a different reference frame, as might happen because of the photons´ high speeds. According to Einstein´s theory of relativity, observers moving at high speeds can get different measurements of the same event because they have different reference frames. But, by performing tests over a complete rotation of the Earth, the researchers ruled out this possibility.

For now, Gisin´s team doesn´t have a good explanation as to how the seemingly instant correlations happen. Even though it doesn´t make sense to them, they hope that others might one day find a better understanding.

In a Nature News story, theorist Terence Rudolph at Imperial College London suggested that humans think that the three dimensions of space and one dimension of time that we´re used to should be the same everywhere, on all scales. But, he says, some things in quantum mechanics might transcend our view of space-time, and we just don´t get to see the whole picture.

"We think space and time are important because that´s the kind of monkeys we are," he said.

More information: Salart, D., Baas, A., Branciard, C., Gisin, N. & Zbinden, H. Nature, 454, 861-864 (2008).

via: Nature News

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itistoday
3.8 / 5 (10) Aug 14, 2008
This is either old, old news, or the reporter did a bad job explaining what the new thing was here.
Velanarris
3.4 / 5 (5) Aug 14, 2008
Agreed, especially since in quantum mechanics (as I understand it) technically the photons aren't in any particular spot if they're not being observed. So how fast is their communication if they are always next to each other in several sets of probabilities, or when they're occupying the same space?

As soon as the word quantum comes in everything kinda becomes a free for all experiment wise. When you measure it the outcome isn't the same as if it was not observed, etc.
SmartK8
2.8 / 5 (4) Aug 14, 2008
It doesn't defy the nature of space dimensions (whatever that means) if they're influencing each other (or even are connected) in some of those eleven dimensions of M-theory or of any other "more than three dimensions" theories for that matter.
Question
2.6 / 5 (8) Aug 14, 2008
I have read many articles over the years about this spooky action at a distance. I have yet to read one that explains exactly what is being communicated from one photon to the other.

If it is the polarization of the light, it is simple, the two are always opposites. This is no difference splitting a coin in 1/2, than sending the halves at random in two different direction. The two will always be opposites here also. Read one you know the other.

There is no communication between these two coin halves or photon whatsoever. But the mythical magic must go on because many peoples livelihoods depend on it.

Einstein was right all along!
solidspin
3.9 / 5 (7) Aug 14, 2008
Question: the spin angular momentum (or just spin) is what is being communicated. The two entangled daughter photons (alice and bob) share the same quantum numbers, but spin is the one that's most easily detectable. Since they're bosons, all the Q #s are the same...so when one of the photon's spins is flipped, then the other reacts MUCH faster than c, to correspond to the same spin value as the first one which was perturbed.
Noumenon
1.8 / 5 (5) Aug 14, 2008
"it seems to defy the nature of space and time, at least from humans´ everyday perspectives;.... We think space and time are important because that´s the kind of monkeys we are,"

Kant had this figured out long ago. The scope of reality that is inescapably entangled with the human mind,... what we call phenomenon, ...must not be all there is, otherwise if it were, in theory we could make sense of it all. There must be no absolute one-to-one correlation between phenomenal reality and noumenal reality.
jburchel
2.3 / 5 (6) Aug 14, 2008
1) Photons do not "KNOW" anything, so I wish lame science writers would quit using this extremely loaded term.
2) These phenomenon, and the "observation" of particles has NOTHING to do with the "HUMAN MIND" and Kant was maybe real smart but his ideas had nothing to do with quantum mechanics nor relativity. Too many Discovery Channel pop science idiots out there. I'm not any expert on this stuff or genius like some of the other posters, but I get so tired of hearing things even I know are complete BS stated as though the writer himself understands something he obviously completely does not... Everybody wants to be smart I guess..
Noumenon
1 / 5 (3) Aug 14, 2008
jburchel, clearly YOU are the one who does not understand. Obviously, phenomenon and observations, and how they are interpreted has EVERYTHING to do with the human mind. Phenomenon does not exist separately from the mind, in other words the definition of it must include mind. Have you read Kant (I have), do you even have a clue what his point was? Doesn't seem like it.
SmartK8
2.8 / 5 (6) Aug 14, 2008
jburchel, ever considered this:

Because of the fact that:

"I'm not any expert on this stuff"

You can prematurely misjudge the:

"things even I know are complete BS"

And because of the fact that you are pissed to a point you create an inadequate reaction which can also be aplied to you in the end:

"as though the writer himself understands something he obviously completely does not"

You can give me and everyone else only one 1. Giving everyone except the ideas you like a bad vote translates to me as entering the room while screaming out all the people who doesn't agree with you. That's just plain rude. I'll give you a little hint. Vote 1 means a spam or really annoying person (in every forum there are few) for me. Not just plain ideas or opinions. There're still possibilities for vote between 1 and 5 you know.. It's not just black and white. Not stopping you thou just consider it.
jeffsaunders
3.8 / 5 (4) Aug 14, 2008
I too have been reeding about spooky quantum entanglement for many years. Quite clearly at times the writers of articles that are supposed to be telling us about breakthroughs quite often forget what it is they are actually talking about. Or at least they forget that not everyone else will know what they are talking about.

Now we have to infer that in this case the topic of discussion is spin of quantum entangled photons.

Some of us still think of a photon as a short wave packet of energy that behaves in some strange ways also like a particle.

There are many people out there that will say "What spin? we are talking about a photon here not an electron aren't we?" and I must sympathise with that point of view completely.

One should be careful about drawing conclusions from facts not in evidence whenever one is presenting a case. I realize these articles are short and must be limited quite drastically and it seems like having links to other reference material is not part of the deal that is a real pity.

1) Do photons really have a spin at all - or is it just a manifestation of our methods of observation?

2) Given that photons have a spin and act like matter (that travels at c?) then can we actually tell reliably what that spin is or are we deceiving ourselves?

3) What method do we have to observe the spin of photons at two distinct locations more than 20km apart and be sure that we are doing this measurement simultaneously to a level of accuracy that is some orders of magnitude greater than the speed of light.

It appears that we can do all that and more. I wont be surprised when next year some clown announces that ... who can guess what will be happening next year. It is bad enough that photons have a spin that can be reversed without difficulty let alone that photons can get entangled to such a degree that the photons themselves cannot tell each other apart (anthropomorphizing for a moment).
OregonWind
2.3 / 5 (3) Aug 14, 2008
The book "Entanglement" - The great Mystery of Physics is a good popular book about this mysterious behavior of Nature.

jeffsaunders
1 / 5 (2) Aug 14, 2008
Looking at this article again - I don't think the entanglement referred to has anything to do with photon spin at all. but then I guess I would have to go and read up a bit to find out what it does refer to.

It occurs to me that light the photon is clocked at speed of c but light the wave must indeed travel faster than this.

Light surely includes everything in the electronic spectrum such as radio waves at one end to gamma rays near the other end.

So the longer the wave length or more correctly the higher the amplitude of the wave then the greater the distance covered. right?

How high can the amplitude go on an electromagnetic wave anyway - the wavelength seems to be infinitely variable at least but what about the amplitude?
Noumenon
2 / 5 (4) Aug 14, 2008
It will travel at c through a vacuum wether it is detected as a photon or wave. Wether its a particle or wave depends on the observation setup. Also, electromagnetism is self propagating, so distance traveled does not depend on wavelength.
RangerMcCoy2
3.3 / 5 (7) Aug 15, 2008
Both QM%u2019s %u201Cnonlocality" and relativity%u2019s ageless photon derive from dx4/dt = ic

A PDF of the paper may be downloaded here: http://physicsmathforums.com/showthread.php?p=10388#post10388

Both QM's "nonlocality"%u2014manifested in the double-slit experiment,
tunneling, and the EPR paradox, and relativity's ageless photon%u2014which
represents time dilation's limit, are founded upon a physical reality
wherein no matter how far a photon travels in the three spatial
dimensions, it yet retains a locality in the fourth dimension,
implying the inherent nonlocality of the fourth dimension which is
naturally accounted for by its fundamental expansion relative to the
three spatial dimensions. The expansion of the fourth dimension
manifests itself as an expanding 3D spherical surface, and every point
on that sphere retains its original compactified locality and
orthogonality, in turn expanding (Huygens' principle), as locality is
"smeared." Hence two initially-interacting photons separated by the
width of the universe may yet influence one-another instantaneously,
as they yet inhabit the same place in the fourth dimension, as
relativity's math also attests to by presenting us with a timeless,
ageless photon whose path through the universe is defined by a null
vector%u2014a vector of zero length, which defines the radius of a photonic
wave's spherically-symmetric, expanding nonlocality.

Time as an Emergent Phenomenon: Traveling Back to the Heroic Age of Physics
In Memory of John Archibald Wheeler
by Dr. Elliot McGucken

ABSTRACT
In his 1912 Manuscript on Relativity, Einstein never stated that time
is the fourth dimension, but rather he wrote x4 = ict. The fourth
dimension is not time, but ict. Despite this, prominent physicists
have oft equated time and the fourth dimension, leading to
un-resolvable paradoxes and confusion regarding time's physical
nature, as physicists mistakenly projected properties of the three
spatial dimensions onto a time dimension, resulting in curious
concepts including frozen time and block universes in which the past
and future are omni-present, thusly denying free will, while implying
the possibility of time travel into the past, which visitors from the
future have yet to verify. Beginning with the postulate that time is
an emergent phenomenon resulting from a fourth dimension expanding
relative to the three spatial dimensions at the rate of c, diverse
phenomena from relativity, quantum mechanics, and statistical
mechanics are accounted for. Time dilation, the equivalence of mass
and energy, nonlocality, wave-particle duality, and entropy are shown
to arise from a common, deeper physical reality expressed with
dx4/dt=ic. This postulate and equation, from which Einstein's
relativity is derived, presents a fundamental model accounting for the
emergence of time, the constant velocity of light, the fact that the
maximum velocity is c, and the fact that c is independent of the
velocity of the source, as photons are but matter surfing a fourth
expanding dimension. In general relativity, Einstein showed that the
dimensions themselves could bend, curve, and move. The present theory
extends this principle, postulating that the fourth dimension is
moving independently of the three spatial dimensions, distributing
locality and fathering time. This physical model underlies and
accounts for time in quantum mechanics, relativity, and statistical
mechanics, as well as entropy, the universe's expansion, and time's
arrows and asymmetries in all arenas.

"More intellectual curiosity, versatility and yen for physics than
Elliot McGucken's I have never seen in any senior or graduate student.
. . Originality, powerful motivation, and a can-do spirit make me
think that McGucken is a top bet for graduate school in physics. . . I
say this on the basis of close contacts with him over the past year
and a half. . . I gave him as an independent task to figure out the
time factor in the standard Schwarzchild expression around a
spherically- symmetric center of attraction. I gave him the proofs of
my new general-audience, calculus-free book on general relativity, A
Journey Into Gravity and Space Time. There the space part of the
Schwarzchild geometric is worked out by purely geometric methods.
"Can you, by poor-man's reasoning, derive what I never have, the time
part?" He could and did, and wrote it all up in a beautifully clear
account. . . .his second junior paper . . .entitled Within a Context,
was done with another advisor, and dealt with an entirely different
part of physics, the Einstein-Rosen-Podolsky experiment and delayed
choice experiments in general. . . this paper was so outstanding. . .
I am absolutely delighted that this semester McGucken is doing a
project with the cyclotron group on time reversal asymmetry.
Electronics, machine-shop work and making equipment function are
things in which he now revels. But he revels in Shakespeare, too.
Acting the part of Prospero in the Tempest. . . " --John Archibald
Wheeler, Princeton University, Recommendation for Elliot McGucken for
Admission to Graduate School of Physics

Dr. Elliot McGucken's Biography: "Dr. E" received a B.A. in physics
from Princeton University and a Ph.D. in physics from UNC Chapel Hill,
where his research on an artificial retina, which is now helping the
blind see, appeared in Business Week and Popular Science and was
awarded a Merrill Lynch Innovations Grant. While at Princeton,
McGucken worked on projects concerning quantum mechanics and general
relativity with the late John A. Wheeler, and the projects combined to
form an appendix treating time as an emergent phenomenon in his
dissertation. McGucken is writing a book for the Artistic
Entrepreneurship & Technology (artsentrepreneurship.com) curriculum he
created.


A PDF of the paper may be downloaded here: http://physicsmathforums.com/showthread.php?p=10388#post10388
gmurphy
1.8 / 5 (5) Aug 15, 2008
I think I speak for everyone when I say KABLAHHH!!!!
Amanullah
2.8 / 5 (4) Aug 15, 2008
thank you mccoy
Ron
5 / 5 (1) Aug 15, 2008
Hi All,
I, personally, don't remember seeing a true photon entanglement experiment done at this large a distance. I think DavidD would have some stuttering to do over this one.
As far as a photon having spin, don't we have to consider it a spin 1 boson if we are using the standard model? Wave/ particle duality or not, as a packet a photon has spin as far as I knew.
Peace,
Ron
Zero
3 / 5 (5) Aug 15, 2008
Guys! This is a truly remarkable experiment in which you have completely missed the point. Even though we use quantum mechanics on a daily basis, quantum mechanics is a theory not a law! It is a very good tool but not the final answer that we are looking for. Entanglement is explained by QM but the fact that information travel instantaneously isn't. This experiment says "Hey this is happening exactly the way it's supposed to by theory but we haven't the slightest clue as to how". The idea is that both Einstein and Schrodinger are wrong and we need something new. This whole ordeal is called a paradox for a reason.
GoodElf
1 / 5 (2) Aug 15, 2008
As I have stated previously this is a matter wave interference effect. The matter wave is "quasi-stationary de Broglie standing waves", any "motion in time" is tied to the proper motion of the sources. Like the similar effect in electromagnetism with bar magnets and static charges there is an extended near field which is subject to interferences that has an influence out to "infinity" as the inverse potential field. Gravity is a standing wave with overall positive curvature and is subject to the zeroth order Bessel Function (Sinc function of sin(x)/x these interferences are seen in connetion with all optical phenomena when influenced by matter ... another case of Bragg's Diffraction at optical frequencies here) and because this is in the evanescent or "gravito-inductive" field (which extends to the edge of our Universe - Mach's Principle) signals propagate at infinite velocity (as they also do for electromagnetic fields while inside their evanescent sources). The difference being the period of oscillation being relatively high in most cases for electromagnetism severely limiting the near field effects and being "infinity" in the case of "gravity" which extends them to "infinity" (note: I am referring to temporal frequency not spatial frequency... two separate entities).

These interferences are the same ones noted when you see colors in soap bubbles. Not the light but the matter waves that influence that light... fringes (at a single optical frequency) that are produced in an interferometer due to the arrangement of planes of matter.

Some additional aspects are here...
http://www.seti.o...com.html
Alizee
Aug 16, 2008
This comment has been removed by a moderator.
Zero
3 / 5 (2) Aug 16, 2008
GoodElf
1 / 5 (2) Aug 16, 2008
I do not think entanglement (or quantum non-locality) is explained by current Quantum Theory except as another unnecessary postulate. Any theory can be made to fit any data with enough postulates. In the past this process led to a cul de sac of the Copenhagen Interpretation which is manifestly experimentally incorrect. For a popular exposition look here...
http://www.thenat...036/NEWS&profile=1036
Quantum Theory has used some ad hoc corrections to enable it to address these issues when other more standard interpretations involving wave packets would have been more appropriate. Alain Aspect has shown that there are some global phenomenon that cannot be explained using quantum locality. Entanglement of photons cannot alone explain the way in which they can be used to signal superluminally. I agree entirely with Dr. Elliot McGucken and I have been independently using these ideas about photon null geodesics on this site for several years. These cannot be used to communicate "alone" across space "instantly" because you cannot beforehand determine the state of any one of a pair of individually entangled photons. Clearly some Wheeler-Feynman Absorber Theory concepts are required to complete this signal process. As in the paper I have linked a "semaphore" can be sent which relies not on "simple binary entanglement" of photons but on ensembles of correlated states being recognized as a binary "bit" interacting with the interferene matter wave over space. The data will not be intelligible without that source phase information you get from an interferometer. The collapse of otherwise of such ensembles depends on the de Broglie matter wave interferences and their "cavity resonances". In the paper referenced previously this was handled by a simple shutter linking with correlated photons on the same spread wavefront. One end was an interference pattern whose integrity depends on cavity matter waves in the space. The "mechanical actuator" effectively shifts the fringes "instantly" throughout the cavity in the Swiss Experiment or collapses the fringes in that earlier paper. Either way a single correlated state tells us nothing since they cannot be predicted but this mechanical "semaphore" which is an analog signal propagates "instantly" to either shift the eigenstate or to collapse it. Since we can't "see" matter waves these need to be passively detected. That is why we need photons and detectors.
Zero
3.7 / 5 (3) Aug 16, 2008
The question is, whether the experiment really means, some information was transfered instantaneously.


1) I have two coins, on both of which one side is heads one is tails. Only one interesting feature of the coins is that when I flip coin 1 and get heads coin 2 gets tails.

2) You and I agree to perform an experiment. We both get synchronized watches and identical rockets and blast of in exactly the opposite directions. Both rockets run out of fuel and stop to a halt when we are 10 light years apart.

3) The experiment I've purposed is this. Every second after the rocket stops we are both flipping the magical coins I had, only I ask you not only record what you see when the coin falls on the table, but also what I see on my table 10 light years away. After doing this for a while a rescue team comes by and brings us back to earth.

4) When we compare our results we find exactly what we were hoping to find. EVERY flip of my coin was EXACTLY recorded by you, and EVERY flip you had was recorded EXACTLY by me.

So riddle me this. If I was 10 light years away how the heck did you know what I was seeing on my table? Shouldn't your knowledge of each flip arrived to you 10 years after the flip happened? But we didn't even flip the coins for 10 years. But you say "Ha! Of course they have a magical connection why wouldn't I know what you saw, it was just the opposite of whatever I had. %u201C
Angular momentum is the magic, and our coins are the photons. So you decide if that was information being transferred or not.
GoodElf
1 / 5 (2) Aug 16, 2008
The short answer is the events were not happening in the "far field" but were in the "near field" (of de Broglie Matter Wave Phenomena). You are not signaling with "light" you are signaling with "gravity" in the near field. The matter waves of the coins have always been there, these matter sources in these coins were not created "yesterday" they have existed for a very long time and have spread "way out there" as an evanescent influence "to the edge of the Universe". Moving stuff move their associated fringes around.

Lets say your coins were both in the "evanescent or near field" of our experiment... flipping a coin is then related to moving a mirror on an "interferometer" related to an associated cavity then this pattern moves from one matter wave eigenstate interference pattern to another in the time that state in the cavity takes to change. This can happen in a perfectly "dark" cavity ... illuminating light is not required to move the matter wave components relative to each other in the one inertial frame all these particles all exist in. We move a mirror of lever... the pattern will instantly move if this actually happens in a "near field". There are many experiments to illustrate this and they are in the literature, that is the way in which the near field differs from the far field. Light differs from gravity by being a stationary "wave".

This does not happen with "particles" (because of the postulate that it is a "particle" without spatial extension according to standard Quantum Theory) it can only happen with matter waves where they "fill" cavities especially when at rest in the near field. Experimentally they indeed do "fill cavities and they are not "particles". De Broglie Theory "works". Now you may say "you know that" but what I say is the Quantum Theory itself does not know that being a particle theory... it is "deconstructionist" and deals with probabilities and "ensembles" of particles and cannot deal with individual "extended particles" as wave packets that spread and chooses to ignore phase since standard Quantum Theory only deals with statistical behavior. We see this behavior with Holograms for instance. This relates to source coherence of sources.

If this is related to the position of a complementary shutter on the other end of the cavity then you are signaling with shutters not with light because these interferences are related to the "placement of planes of matter" not with "transmission in the far field of light signals". To detect these changes in cavity matter wave geometry we use photons correlated at the sources and the sinks to provide us with a set of fringes we can correlate with. It so happens that the photons at both ends of the "interferometer" are correlated so what happens to one of a pair of these "correlated" photons can affect the state of the other. This "signal" is actually an analog signal (we are not using individual photons to signal they are fringes... and these fringe patterns are constructed using many individual photons one at a time) not a digital one and is a phenomenon that is not restricted to distance. Interference patterns can be constructed from the light from distant stars so only correlation is required over distance. In the case of distant stars we do not have the ability to send messages in this way because we lack the correlated "pair" of photons. Messages are "out" at present for signaling to aliens unless they set things up for us... he he he!

What we have is a tuned cavity with source and sinks resonantly tuned to the cavity state (call it a "squeezed state" if you like) a spatial resonance but the matter waves have no temporal component since they are standing waves. However proper motion of components of matter in the evanescent field will instantly "move the matter wave" associated with that component relative to the other components even at great distance. Of course the cavity must be set up so that the signal you want is the one you finally get, delicate mechanical adjustment is required. The matter waves of the cavity have almost always existed since the particles that composed that matter were created and as part of a universal matter wave field extends "already" to the "edge of our Universe" through Mach's Principle... particle by particle these wavelets add up... sometimes to "something of nett phase effect" such as in crystal planes and in chaotic matter the sum is only a "tiny residual phase" component that can't usually be measured. What is not blocked or scrambled is the gravitational "potential" component which can pass through anything without phase shift or attenuation. Gravity is a near field or evanescent phenomenon of individual matter wave particles interfering with each other. This experiment demonstrates that clearly if it was ever an issue. The sinc function shows how it works and what you can measure are these fringes. Usually these are "individually" lost over great distances when we try to measure the effects in general but in a particular case we may arrange planes of matter to "amplify this coherence" along certain directions of space. This is called Bragg Diffraction if you use less coherent X-Rays but exists at all frequencies even down to visible light waves and so on ... even radio waves as a "cavity resonance" and coherent phenomena can utilize it to great effect. Only the size and states of resonant structures change.

Here is an example of this "entanglement collapse" in the literature which shows how this interference "never dies" and extends to "infinity".
"Localization by entanglement"
J. Brand1(a), S. Flach2, V. Fleurov2,3, L. S. Schulman2,4 and D. Tolkunov4
1 Centre of Theoretical Chemistry and Physics, Institute of Fundamental Sciences, Massey University Auckland New Zealand 2 Max-Planck-Institut f%uFFFDur Physik komplexer Systeme - N%uFFFDothnitzer Str. 38, D-01187 Dresden, Germany, EU 3 School of Physics and Astronomy, Tel Aviv University - Tel Aviv, Israel 4 Department of Physics, Clarkson University - Potsdam NY, USA
received 22 December 2007; accepted in final form 25 June 2008 published online 5 August 2008
PACS 03.75.Gg %u2013 Entanglement and decoherence in Bose-Einstein condensates
PACS 05.45.-a %u2013 Nonlinear dynamics and chaos
PACS 11.15.Kc %u2013 General theory of fields and particles: Classical and semiclassical techniques
Abstract %u2013 We study the localization of bosonic atoms in an optical lattice, which interact in a spatially confined region. The classical theory predicts that there is no localization below a threshold value for the strength of interaction that is inversely proportional to the number of participating atoms. In a full quantum treatment, however, we find that localized states exist for arbitrarily weak attractive or repulsive interactions for any number (> 1) of atoms. We further show, using an explicit solution of the two-particle bound state and an appropriate measure of entanglement, that the entanglement tends to a finite value in the limit of weak interactions.
Coupled with the non-existence of localization in an optimized quantum product state, we conclude that the localization exists by virtue of entanglement.
http://epljournal...tion=toc&url=/articles/epl/abs/2008/16/contents/contents.html
So we can understand how this entanglement extends... there is a diagram that shows that in a full quantum treatment... one that is not usually given and we can see that phase and this localizations "never dies" in the same way that "gravity" only attenuates with distance. This can be understood in a Theory of Gravity that includes Matter Wave Phase for individual quantum de Broglie matter wave "sources".

Here is a paper that appears to show that matter waves are correlated intercontinentally...
"Intercontinental quantum liaisons between entangled electrons in ion traps of thermoluminescent crystals" Robert Desbrandes (Louisiana State University) and Daniel L. Van Gent (Oklahoma State University)
http://arxiv.org/.../0611109
Here is an experiment which shows superluminal effects in evanescent fields...
"Superluminal propagation of evanescent modes as a quantum effect" : Zhi-Yong Wang, Cai-Dong Xiong, Bing He
http://arxiv.org/...0347.pdf
There are many examples... clearly the theory works if gravity and matter waves are "quasi-stationary near field" temporal phenomena with far field spatial phase influences dependent on de Broglies relationship in cavities.
DLuckyE
1 / 5 (1) Aug 17, 2008
I don't get the part about the reference frame of light being excluded due to the rotation of earth. The rotation of earth wouldn't even matter at the light's reference frame since everything is at a single point there with no time.

Or am I missing something?
ShadowRam
3 / 5 (2) Aug 18, 2008
I have read many articles over the years about this spooky action at a distance. I have yet to read one that explains exactly what is being communicated from one photon to the other.

If it is the polarization of the light, it is simple, the two are always opposites. This is no difference splitting a coin in 1/2, than sending the halves at random in two different direction. The two will always be opposites here also. Read one you know the other.

There is no communication between these two coin halves or photon whatsoever. But the mythical magic must go on because many peoples livelihoods depend on it.


My thoughts exactly,
ShadowRam
3 / 5 (1) Aug 18, 2008
The question is, whether the experiment really means, some information was transfered instantaneously.

4) When we compare our results we find exactly what we were hoping to find. EVERY flip of my coin was EXACTLY recorded by you, and EVERY flip you had was recorded EXACTLY by me.


Show me proof of an article that goes beyond the just 1 flip...
CaptSpaulding
5 / 5 (1) Aug 18, 2008
I think we have all been trolled enough by the philosophy/left field pop sci writers for one day. This is not an article on existance, ethics, or the scientific method (unless theirs is flawed, which I don't think this article gives near enough information to answer that question and honestly I don't think they are sure about that part). Please, no more copy/pasta of entire papers into the comment box, it's annoying at best. Summarize it, then let others give it a big fat 1 or an awesome 5.

Now on topic:
Sounds to me that there might be another dimension in play in the experiment. Baring a tiny wormhole in spacetime connecting the photons, I'm going to guess that this might just be something that needs a further refinement of QM to solve (see M-theory, etc.). So yes, I'm generally agreeing with SmartK8 and others.
SentientMarine
not rated yet Aug 18, 2008
CaptSpaulding your idea of a tiny wormhole is interesting as time may be a factor but wouldn't it require a second counter connecting worm hole to bring the information back to this reference frame?
Velanarris
not rated yet Aug 18, 2008
I don't get the part about the reference frame of light being excluded due to the rotation of earth. The rotation of earth wouldn't even matter at the light's reference frame since everything is at a single point there with no time.

Or am I missing something?


Greater motion is greater energy. Energy and mass can be related, more mass = more gravity so technically by the theories motion increases mass.

Yes the above is a very dodgy explanation.
GoodElf
5 / 5 (1) Aug 19, 2008
The idea of "wormholes" connecting photons is really from far left field. I do not think many real scientists would agree with that idea (if any). While entanglement is a mystery to many it is not the basic issue of this article. The issue is not about the connection between entangled pairs of photons instantaneously... It is about near instantaneous communication of intelligible signals in the rest frame of the experiment over this large range.

In case people are unaware of this, the article is closely associated with another article previously published here and in other science news sites recently...
http://www.physor...327.html
This information is sufficient to allow you to get the actual paper. I suggest a read of that paper first.

My previous answer was long because it is complex and requires some background in optical theory. If you don't get entanglement already you will probably not get what this discussion is all about.
Alizee
Aug 19, 2008
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Alizee
Aug 19, 2008
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Alizee
Aug 19, 2008
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GoodElf
not rated yet Aug 19, 2008
I even still didn't get completely, how they achieved the "space-time separation" claimed....
I am not a believer in Aether Theories so I do not require that concept. I happen to think Einstein theories are sufficient in this case. I believe that what is stated in the paper is space-like separation not time-like separation (so it is not spacetime like if you get the drift here). Photons that have a common source when they are created are entangled at the source. The two separate photons are quanta so they are absorbed in a sink separately but this collapses one of the cavity states and therefore instantly affect the cavity state of the other likewise expanding "superimposed" photon. Meaning... from the point of view of the experiment the "endpoints" are space-like separated not time-like separated on the lightcone wall. Photons "spread" at the speed of light and are then "state collapsed" together if they are "entangled at source". Ignoring the way in which the fibers are physically lain over the landscape the endpoints are on the "exact" same time delay from the common source of the two entangled photon's BBO crystal. One of these pair of photons goes one way and the other goes the other way (actually they both expand as superimposed orthogonal photon states in the one cavity). We cannot say which one goes one way or the other... quantum theory states these "bosons" are in the same quantum state together but are separate but linked quanta. They are two "waves" spreading from the exact same source in a single simply connected cavity. This means that when you "interfere" with one photon of the pair of source entangled photons at one end (despite the spatial separation), this is "exactly" on the same expanded wavefront as the twin photon on the other end of this "fiber interferometer" cavity. Therefore if you collapse the wavefront of one of the source entangled photon pair this instantly "sets" the state of the other (which was in the same superimposed boson state). In this case one photon is "read" as being left hand polarized and then the other will be right hand polarized (but otherwise identical). What cannot be done is specifically select the state of a particular one of these pair of photons to collapse. Usually this fact prevents a semaphore being transmitted even though the individual BBO entangled photons are always entangled in the cavity as their mutual wavefronts expand at the speed of light.

In this case the semaphore is not the specific state of each photon (which cannot be predicted) but the collective state changes induced from one end due to a change in the cavity matter wave geometry.

Think of this as an interference pattern of maxima and minima that moves when you "collapse the state". A polarizer collapses the state of half of the photons or a shutter or mirror affects all the entangled photons in one half of a "cavity". You could use a polarizer or a shutter or mirror and the fringes will be affected by a mechanical movement of that "matter wave component". An actual interference fringe requires many photons to be detectable but the maxima will "move" relative to the minimia depending on which group of photons are affected. The fringe may be also entirely lost if all photons are decohered together. The angle of the cut on the BBO crystal can separate one group of photons from the other birefringently. The moving of a fringe will happen instantly at either end depending on the mechanical state of the "interferometer" which is a "cavity" that shows these "interference fringes". The concept is stated in that paper as a movement of a mass... all matter wave fringes... even with a soap bubble depend on the position of planes of mass. An interferometer is just such a system that shows the accurate positions of planes of mass at either end of the cavity. Light is simply resonating in the cavity created by the positioning of these planes of mass. Some spatial optical filters are commercially designed to resonate according to the spacing between the reflecting planes in the filter and thereby pass only one frequency of light for instance... like the pretty colored patterns formed of oil on water. Pairs of entangled photons will move together in synchronization as indicated in this other recent experiment...
http://www.physor...362.html
Here are two identical entangled images ... where one image is missing one of a pair of entangled photons and this is "complemented" in the other beam and visa versa. Yet the image of the cat remains as an "ensemble" This "spacelike non-locality" defies standard quantum theory but is logical in spreading photons that are eigenstate dependent not position dependent and not local as a particle would be.
Alizee
Aug 19, 2008
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GoodElf
3.7 / 5 (3) Aug 20, 2008
"Sorry man, I get completely lost in the second sentence of your already. Which "drift", "sink", "collapsing cavity states", "expanding superimposed photon" are you talking about? Can somebody explain, what this guy is saying?"

Sorry if I have lost you so I will try and explain (please forgive the length of this explanation again)... We have a colloquialism where I come from to "get my drift" means to understand the direction (or "drift") in which the argument is heading.

A "sink" is the opposite of a "source" of photons. Photons are not subject to conservation laws the same way as matter particles like electrons and protons which cannot be created individually on demand. Photons can be created and destroyed at will but they still obey quantization rules. They "appear" to come from a "source" and spread in space then collapse into a modal spatial eigenstate in a "sink" (see reference below). The analogy is a faucet or tap is a "source" of water and the drain hole in a bath is a "sink" for the same water... hence a "source and a sink". The "bath" itself could be thought of as a "cavity" (or Transmission Line) that "contains sources and sinks"... This is a "water analogy"... of course.

With photons or all propagating coherent electromagnetic phenomena which include Gamma Rays, XRays, Radio Waves, Microwaves, Visible Light and many other EM Bands... light spreads from a coherent "source" (such as a LASER or even a Broadcast Antenna) as a superposition of uncollapsed quantum states of individual quantum packets each carrying an energy E = hf where f is the base frequency. These "packets" contain higher frequencies which define and truncate this wavelet but they all act together as a single "wave packet of energy". These coherent photons are all "source coherent"... the phases of all photons "start" at the same place or are "reset" by some cavity geometry (zero phase is usually an antinode.. the source LASER or antenna is "driven" by an energy source) and the emitted photons are absorbed at a sink and end in or very near another antinode or resonant sink (orthogonal phase) to which the photon is "matched" as in Transmission Line matching of source to sinks (load). For instance television is a case of a driven source antenna (TV Channel) and many passive antenna sinks on the roofs of homes with associated tuned circuits and a means tp decode the information and display it. The "source" and the "sinks" are matched resonating pairs. These photons can only be absorbed in a "sink"as a whole or not at all, that what it means to be quantized. The photons may also have different states of polarization and even a single polarization may actually be composed of a "superposition" of other uncollapsed "eigenstates" which are composed of other possible polarizations (at different angles for instance).

These states cannot be predicted in advance and they are said to carry a "quantum bit" of information or Qubit from the "source to the sink". This Qubit may be measured as a polarization state of the individual photons. In entangled photon pairs, these are specially prepared, neither propagating entangled photon has a state and both exist in 'superposition" of possible outcome states until one of the photons is "read" to be, say, left hand polarized or right hand polarized then the other Qubit associated with the other entangled photon will be the orthogonal polarization state (... the other one). This is the "two sides of a single coin" mentioned. A quantum bit differs from a digital bit by being not just the values "1" or "0" but "1 and 0 at the same time" and the "outcome" is not determined till it's value is read ... between states it is said to be in a superposition of all possible eigenstate outcomes... and several may act together as a coherent whole. When coherent photons are "sinked" they are "sinked" in a single collapsed eigenstate which relate to the transverse modes of propagation of light in cavities... An eigenstate is related to a "cavity resonance state" like when you "ring" a large bell or resonator it has a series of standing wave states of nodes and antinodes mapped over it's surface... these are the stable collapsed eigenstates of a bell.

http://en.wikiped...rse_mode

This "Bell" experiment mentioned though is related to John Bell and the now famous demonstration of quantum non-locality and the "Bell inequality" and the confirmatory experiments by Alain Aspect. This "detection" of the single photon is "measured" as a single event but the other entangled photon is linked to the first state and it's "measured value" so in that restricted sense we have two "particles" with "essentially" the same identity. A pair of entangled photons, therefore, are two separate photons linked by a single set of orthogonal quantum states. Many individual photon events from a single LASER source are required to "map" these modes completely because each photon only carries a single "spot" of data on a "screen" though it is linked to the entire state. These modes are cavity solutions for electromagnetic radiation where the phase and "intensity" vary spatially over a detecting surface such as a gridded array of photocells like you might have in your domestic digital camera.
Alizee
Aug 20, 2008
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earls
not rated yet Aug 20, 2008
What are these "orthogonal quantum states"?


Simply put - the opposites. If one is up, the other is down.

It has to do with photons' vectors of travel and the photons' polarization states on those vectors. The polarization is perpendicular to the vector of travel and "entangled" (opposite) at either end.

(shot in the fog)

States of what?


The polarization of the photon.

Why this set is "single"


Because there is a single entanglement event! Although the photons are separate physical entities, they are in essence one of the same - separated in space.
Alizee
Aug 20, 2008
This comment has been removed by a moderator.
GoodElf
not rated yet Aug 21, 2008
..simply put - the opposites. If one is up, the other is down..although the photons are separate physical entities, they are in essence one of the same....
So are these photons the same, or the oposite?

Once again I need to apologize for the length of this explanation. The answer given by earls was pretty much correct... thanks for that. Your question Alizee... The photons are never "the same", That is not what entanglement means. They share a common property of "orthogonally". This means it is like the way a coin is only a single object yet it has a "head" and a "tail". There are no entangled photons sharing the same identical property in nature (though there are a couple of double headed coins out there... he he he!). However, in a game of chance, when you flip a coin it may come up heads... but if on close inspection the other side of the coin was to show heads too I think there would be some "disapproval" generally. In entangled photons the property for one could be a left hand polarized photon, instantly following on, no matter how far away the other photon is, it's property will always be right hand polarized photon. The change occurring at that instant the first photon was "read". But because you can't choose (like when you flip a coin) for it to come up a head or a tail on demand (yeah!... I know you can cheat with coins but aside from that...) you can't "signal" using this property in these circumstances using photons even if the "speed" at which this process occurs is "infinite"..

There are a lot of stories and experiments associated with this property and you can "partially collapse the state" and in theory you can even "unread the photon Qubit" after it has even been collapsed in some cases but this process actually "causes the Universe" to forget what the measurement would have been.

So the answer to your question is the photons are neither the same nor opposite... they are "entangled", they are very special photons prepared in a certain way to make them "very special". This special property you do not see on our scale of observation so this new idea of "entanglement" is supposed to differentiate the concept from "same" or "opposite".

You can argue all day about why the "state" of the two separate photons are the "same" and also why they are "opposite" and in one sense they are indeed the "same" and they are indeed "opposite".... just like the heads and tails on a coin as mentioned above. It would only be a semantic game. I will still point out "these" entities are not a coin... that's the catch. It is something "new".

Entanglement ... Why? The answer to this IMHO lies in the wave nature of the spreading entangled photons. They start in the same place and they spread to all the same places at the speed of light so in a sense they are always "superimposed" on each other (occupying the same space on the wavefront). Actually the act of "reading" a photon property is what causes the photon to be where you "read" it. It can only be read when it has sufficiently spread to that place you are reading it to actually read it there and not before. Photons "spread" at the speed of lioght and though this is quite fast it is by no means an infinite velocity. Also photons can't move slower than light so they can't "lag behind" either. To catch one you got to get it "when it passes bye". When a photon "resonates" it may "pass bye" several times though.

Photons are "read" on the wavefront of the spreading wave when it reaches the detector (the detector can resonate)... That is like when a wave hits the beach... if you want to measure the wave you got to time that measurement when it hit the shore. You can time other waves but if you want that special wave you need to know when it arrives. When you "read" the state of one of the photons this "forces" the polarization state of the other entangled photon (or at least this is how I interpret it). You can read that other photon "later" in time (because reading the first photon does not stop the second photon from moving away from the source ... ) but the second photon continues to "spread" at the speed of light and it will have that orthogonal polarization "impressed" on it from the first read of the first photon.

Here is one possible way to think of it...The first "read" operation "collapses" the electric and magnetic field of the first entangled photon... IMHO the changing electric and magnetic field of this "superimposed" photon "when it is read" induces an opposing "flux" in it's entangled twin making it "opposite" and this has nothing to do with distance of separation since this photon and it's superimposed twin always traveled together in an uncollapsed state. Where one photon's state is "read" is like measuring the temperature of a lake at one point on the shore. You know the temperature only where you read it. With this system of two entangled photons it's twin will have the same reading on the other side of the lake because they occupied the same superimposed state. Why is one photon so distant from the other on the other side of the lake? That is because that is where you choose to read it... it causes it to "collapse" to that point so it can be read. Here is an analogy.. Like a balloon can be inflated to fill an entire room and you can "prick the balloon anywhere in the room" where it presses against the wall and the balloon will collapse everywhere in the room. The prick is at one point in the room but the collapse is "global". With all photons "measuring" or "reading" them collapses the state (like the inflated balloon). A photon is like an expanding balloon and will expand until it reaches a detector at which time it's quantum qubit may be "read". Like the balloon the measurement of the photon property can usually only be made once... then "bang" ... it is gone. With two "entangled" photons it is like two balloons that fill a certain room (a cavity) together (maybe one immediately inside the other). We place two pricking devices in the room on opposite sides, one pricks one and only one balloon and the other can only prick the other balloon. Prick the first balloon lets just say it changes the color of the second balloon "to complement" it. This measurement tells us the first balloon color. Prick the second balloon it has the color that you predicted from measuring the color of the first balloon... the opposite.

You will ask the obvious question "couldn't the photons always been a particular polarization (a particular color) each and when we measure one the other photon was always simply the opposite polarization always?" Not according to the experiments that determine these properies and the arguments are very complex... too complex to discuss here. I have not discussed spin quanta. either.. as well as the polarization they can also be entangled too. Having to describe "quantum spin" is very complex so I avoided that. Matter waves are also able to be entangled... that too was not discussed here.