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Physicists Create Quantum Link Between Photons That Don't Exist At the Same Time

samzenpus posted about a year and a half ago | from the time-after-time dept.

Science 364

sciencehabit writes "Physicists have long known that quantum mechanics allows for a subtle connection between quantum particles called entanglement, in which measuring one particle can instantly set the otherwise uncertain condition, or 'state,' of another particle—even if it's light years away. Now, experimenters in Israel have shown that they can entangle two photons that don't even exist at the same time. Anton Zeilinger, a physicist at the University of Vienna, says that the experiment demonstrates just how slippery the concepts of quantum mechanics are. 'It's really neat because it shows more or less that quantum events are outside our everyday notions of space and time.'"

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Wait for the retraction (0, Flamebait)

ssufficool (1836898) | about a year and a half ago | (#43800171)

Faster than light speed is possible... but wait, we need "Exotic" materials that don't exists. We entangled particles to communicate across time and space, no wait. we measured it wrong. I give it a week before other scientists call bullshit.

Re:Wait for the retraction (0)

Anonymous Coward | about a year and a half ago | (#43800209)

You really have no idea what you're talking about do you?

Re:Wait for the retraction (-1, Troll)

Progman3K (515744) | about a year and a half ago | (#43800225)

Oooh, called out by anonymous coward who doesn't postulate anything... Edgy

Re:Wait for the retraction (-1, Offtopic)

narcc (412956) | about a year and a half ago | (#43800325)

Oooh, calling out an anonymous coward who didn't even postulate anything... Edgy

Re: Wait for the retraction (0, Offtopic)

Anonymous Coward | about a year and a half ago | (#43800347)

Ooooh. So much edginess.

Re: Wait for the retraction (1, Offtopic)

dmbasso (1052166) | about a year and a half ago | (#43800381)

Ooooh, So much ooohs.
Somehow, suddenly I want to play Monkey Island again.

Re: Wait for the retraction (1)

dmbasso (1052166) | about a year and a half ago | (#43800851)

s/much/many/g

Just waking up and writing in non-native language requires coffee.

Re:Wait for the retraction (2)

socceroos (1374367) | about a year and a half ago | (#43800213)

The problem with quantum mechanics is that we suck at measurement. This really does put a spanner in the general workings of testing scientific theory.

Re:Wait for the retraction (1)

Z00L00K (682162) | about a year and a half ago | (#43800223)

If it is actually possible to utilize the entanglement there are a number of commercial possibilities as well as governmental. Communication that is hard to spy on, faster communication across the globe, instant communication with remote operated vehicles on other planets.

But we don't know until we have freed Schrödingers Cat - or has it actually teleported itself to another plane of existence?

Re:Wait for the retraction (1)

dgatwood (11270) | about a year and a half ago | (#43800525)

I'm pretty sure we already know the answer. The cat is dead. Curiosity killed it. [iwastesomuchtime.com]

Re:Wait for the retraction (0)

Anonymous Coward | about a year and a half ago | (#43800573)

you can't transmit information faster than light. also states so in the article. not that i understand why.. spy-proof communication is probably feasible, though.

Re:Wait for the retraction (0)

Anonymous Coward | about a year and a half ago | (#43800715)

Or it must have been there in the future?

Re:Wait for the retraction (1)

kermidge (2221646) | about a year and a half ago | (#43800237)

Let me guess, tl;dr?

Re:Wait for the retraction (0)

Anonymous Coward | about a year and a half ago | (#43800247)

Faster than light speed is possible

We already knew that. Whatever gravity is it already shows us this. The Earth is approx. 8 light-minutes from the Sun. The Sun is of course moving. If the Earth revolved around where the Sun was 8 minutes ago, it would long ago have drifted out of the solar system. Gravity operates faster than light.

Re:Wait for the retraction (0)

Anonymous Coward | about a year and a half ago | (#43800277)

I think you'll find gravity wibbles a bit, sort of like rubber the motion of the sun flows down that rubber bit at the speed of light and affects the position of our planet 8 minutes after the sun has since moved but since it's a more dynamic relationship due to the effect of gravity, we continue to follow the sun.

Re:Wait for the retraction (2)

mark-t (151149) | about a year and a half ago | (#43800287)

The same forces that are moving the sun through space are also acting on the earth itself. So, no.

Re:Wait for the retraction (5, Informative)

Pseudonym (62607) | about a year and a half ago | (#43800521)

Yeah, this. What the AC may be confused about is that faster than light travel is (as far as we know) not possible in space, but the distance between two points can increase faster than light could travel because there's nothing stopping space itself from expanding that fast.

Re:Wait for the retraction (1)

Anonymous Coward | about a year and a half ago | (#43800593)

The distance between two objects does not increase faster than light relative to each other. You need to study the Lorenz transformation equations.

https://en.wikipedia.org/wiki/Lorentz_transformation

If one object far away is moving .9 times the speed of light away from you and another object, in the opposite direction, is moving .9 times the speed of light away from you then those two objects, relative to each other, are not moving faster than the speed of light away from each other. They are moving like .99 (or whatever, you have to do the calculations) times the speed of light relative to each other.

Re:Wait for the retraction (2)

maxwell demon (590494) | about a year and a half ago | (#43800619)

Lorentz transformations only cover special relativity. In general relativity, you can indeed have the distance between two points grow faster than light. Of course not if the points are at the same place.

Re:Wait for the retraction (1)

Pseudonym (62607) | about a year and a half ago | (#43800659)

Precisely.

OK, not precisely. Two points at the same place at the same time is one point, not two points. But I knew what you meant.

Re:Wait for the retraction (5, Informative)

quax (19371) | about a year and a half ago | (#43800451)

We already knew that.

Whatever "we" you mean count me out.

According to GR gravity is facilitated via a retarded potential [wikipedia.org] , and of course GR survived so far every conceivable test and has been shown to make correct predictions were Newtonian gravity failed.

So no, gravity does not operate faster than light.

Re:Wait for the retraction (2)

Gogogoch (663730) | about a year and a half ago | (#43800457)

Rubbish. Gravity is not FTL, and your argument is BS.

Re:Wait for the retraction (0)

Anonymous Coward | about a year and a half ago | (#43800513)

The Earth does revolve around where the sun was 8 minutes ago.

Re:Wait for the retraction (1)

shentino (1139071) | about a year and a half ago | (#43800625)

Except that the Earth's motion relative to the galactic core already roughly matches that of the Sun (relative to the galactic core).

Lern2frameofreference.

Re:Wait for the retraction (1)

MaxToTheMax (1389399) | about a year and a half ago | (#43800335)

Possibly using excessively hostile phrasing, but this poster is right-- I'd say the chances of the results not being reproducible are high.

Re:Wait for the retraction (1)

Gogogoch (663730) | about a year and a half ago | (#43800473)

I doubt this is BS, sounds authentic to me. Quantum mechanics is weird. As for the "outside ... space and time", note that the missing words from TFA are "outside everyday notions of space and time". In other words, outside our common sense.

Re:Wait for the retraction (0)

Trax3001BBS (2368736) | about a year and a half ago | (#43800767)

I give it a week before other scientists call bullshit.

I see it as something they wanted to prove and did to themselves and anybody else who wants to believe their results or just their word.

Entanglement is related to particles from the same event. 1&2 are entangled as are 3&4.
1&4 were considered entangled by their use of "projective measurement" on 2&3

"projective measurement" = Although quantum mechanics has held up to rigorous and thorough experimental testing,
many of these experiments are open to different interpretations
http://en.wikipedia.org/wiki/Interpretation_of_quantum_mechanics [wikipedia.org]
linked from http://en.wikipedia.org/wiki/POVM [wikipedia.org] defining "projective measurement" (first paragraph).

So they have their interpretation, I have mine (didn't happen), and we're all happy.

About me: A two years of chemistry ex-student who does a lot of reading on quantum physics. Yet nobody to talk on the subject, so more reading.
Not trying to solicit anybody just saying nobody I know, knows much on the subject to bounce thoughts off of.

I give... (1)

Anonymous Coward | about a year and a half ago | (#43800181)

OK, it's official. Science and technology is accelerating so fast that I can no longer keep up.
Happy?

Re:I give... (1)

socceroos (1374367) | about a year and a half ago | (#43800205)

Subtle. Very subtle...

Re:I give... (1)

Black Parrot (19622) | about a year and a half ago | (#43800371)

Not edgy, like the previous thread?

Re:I give... (1)

socceroos (1374367) | about a year and a half ago | (#43800441)

Can you have something that is both subtle and edgy at the same time? A superposition of the both states?

Photon model broken (4, Insightful)

Anonymous Coward | about a year and a half ago | (#43800203)

'It's really neat because it shows more or less that quantum events are outside our everyday notions of space and time.'"

No, not really. You're simply see the macro effects of partial photons interacting, and unwilling to give up the idea of the discrete photon.

If all you can see (and measure) is a photons promotion and demotion of electrons, you an only see the fast shift of the big circles jumping around in this picture, not the slower smaller drift that is happening.
http://i.imgur.com/AUXb2N9.gif

Give up your photon model, it's based on a faulty understanding.

Re:Photon model broken (1, Insightful)

Laxori666 (748529) | about a year and a half ago | (#43800235)

+1

Re:Photon model broken (2, Insightful)

Anonymous Coward | about a year and a half ago | (#43800353)

Well, so quantization of energy is wrong then? If you can have "fractional photons", then the Rayleigh-Jeans formula is completely correct. Never mind that it predicts that all blackbodies should be emitting radiation with infinite power.

Observation vs model (3, Interesting)

Anonymous Coward | about a year and a half ago | (#43800417)

If I had a machine, and it could only see the large circles, then all I would see is the large circles.
If I then made a model of how the large circles appear and disappear, that model would be correct, it would fit the data, it would show the probability of the circles appearing as they jump around. Those circles will jump, they'll go backwards in time, they'll do kinds of weird things.
So my equations all work, and my model of jumping circles works, ergo my model is correct?

Except it isn't, its a function of the limitations of the machine used to observe the underlying effect.

"then the Rayleigh-Jeans formula is completely correct. Never mind that it predicts that all blackbodies should be emitting radiation with infinite power"
So how fast is light really traveling in this crazy new world?

Re:Observation vs model (1)

umghhh (965931) | about a year and a half ago | (#43800763)

Interesting argument. Come to think of it current physics are so complex, difficult to comprehend and counter intuitive that our ape's brains usually fail there. What this means to me is that we really are apes and have problems understanding the reality as it appears to be in its quantum and other aspects or maybe the reality is not measurable with our means at least currently. In both cases the poor soul on top of the ape brain has a problem with tools - only the tools in each case are different: one is brain the other technical methods of measuring and proving our ideas. Come to think of it nothing has changed from times Plato wrote about men chained in the cave watching the wall and shadows on it. It may be that this is more accurate theory of everything than anything else we have devised since. Utility of this theory of everything is that we should be very skeptical about things that we think are real.

Re:Observation vs model (1)

dargaud (518470) | about a year and a half ago | (#43800827)

I really wonder what would happen if you kept a kid in the dark and only taught him about quantum mechanics... Would the understanding be more innate ? Or would the fact that we still need to explain it in everyday words and usual reality-based maths lead to the same interpretations ? Yeah, I'd make a terrible father.

Re:Observation vs model (1)

ron_ivi (607351) | about a year and a half ago | (#43800865)

Perhaps something similar to what you suggest -- still teach the easy approximatoins -- but from the first day in high school physics start with the real solution (even if they don't understand it) and show how the stuff they'll be doing is a convenient approximation (in the same way that second grade math teaches kids rounding to the nearest 10).

That way from the beginning they'll be wired to accept that the truth is bigger than "gravity's uniform everywhere" or e=m*c*c without the momentum parts even if they use the shortcuts on tests that year.

Re:Photon model broken (4, Insightful)

VortexCortex (1117377) | about a year and a half ago | (#43800405)

The world is made of 4 basic elements, earth, air, fire, water.... No, scratch that, there are a bunch of elemental stuffs, the most holy of which is quicksilver, the universal element... Wait, no, there are over a hundred chemicals with different properties. Ah, look, see, there are atoms, you know, and inside these atoms you have electrons, protons, and neutrons -- See, that's what gives the atoms their properites -- And, wait, the sub atomic particles are made of Quarks, and -- No, there's a zoo of particles, and fields and they all interact in these little quantized packets / waves, Quantum Physics -- No, wait the quanta.......

The rabbit hole is very deep indeed. Better tools show us finer structure. I agree. It would be exceedingly arrogant and foolish to think of light as "photons". We have only approximations, and they are always a bit wrong.

Re:Photon model broken (4, Informative)

Pseudonym (62607) | about a year and a half ago | (#43800527)

The world is made of 4 basic elements, earth, air, fire, water...

Today, we call them "solid", "gas", "plasma", and "liquid" respectively.

Re:Photon model broken (5, Funny)

The Mighty Buzzard (878441) | about a year and a half ago | (#43800705)

And Leeloo.

Re:Photon model broken (0)

Anonymous Coward | about a year and a half ago | (#43800745)

I dunno nothing about this physics stuff, but I can tell you that you are wrong.

I just took a dump, and it sure wasn't solid or liquid. It was a solid liquid with some gas.

Re:Photon model broken (2)

10101001 10101001 (732688) | about a year and a half ago | (#43800519)

Well, I tend to think of quantum mechanics as proving the universe functions on call-by-need [wikipedia.org] , with faster than light being the lack of support for mutation. Entangling then is really just call-by-need evaluating out a circumstance backwards far enough to note that when two waves/particles/whatever were at the same place, they had to have certain exclusionary properties (for the article, one photon was polarized vertically and the other horizontally) which cause the interpretation of entanglement.

Of course, all of the above says nothing of the how or why of it. And no doubt, I'm likely far off in really understanding on quantum mechanics. But, it at least helps me better understand it.

Re:Photon model broken (1)

maxwell demon (590494) | about a year and a half ago | (#43800595)

Actually, there's a very simple interpretation of this experiment which doesn't need entanglement over time at all:

First, you create a normal entangled pair (no over-time entanglement involved).

Then, you measure one of the photons, breaking entanglement. The other particle now has the corresponding state. If we were to measure it immediately, we'd find the correlations with the first photon we use to detect entanglement that was present before the first measurement.

But we don't immediately measure it, but we use a second pair of entangled photons to quantum-teleport it. Note that there's no entanglement swapping going on here, because there's no longer entanglement in the first photon. It's just normal quantum teleportation (well, actually entanglement swapping is also just quantum teleportation of an entangled particle). Of course the teleported photon has the same state as the non-teleported.

Now the teleported photon is measured. Of course we find the correlations with the first-measured photon. That doesn't mean this photon was ever entangled with the original one.

Re:Photon model broken (1)

bug1 (96678) | about a year and a half ago | (#43800597)

Dude, its, like, totally real, man.
The photon is chillin with the physicists at an event in the parallel university after it went through teh wormhole.

Can i have my grant money now ?

Re:Photon model broken (0)

Anonymous Coward | about a year and a half ago | (#43800601)

Ya, unless you've done graduate level quantum physics, I think you need to STFU.

Re:Photon model broken (0)

Anonymous Coward | about a year and a half ago | (#43800629)

It really is amazing the sort of pseudo-intellectual drivel that Slashdot finds to be "insightful".

Re:Photon model broken (3, Interesting)

tonywestonuk (261622) | about a year and a half ago | (#43800681)

I believed as you did. Then I read this http://quantumtantra.com/bell2.html [quantumtantra.com] - Its like Quantum physics , without the maths, and for the it literate.

Changed my ideas on what QM was all about.

Go read it. Seriously.

Re:Photon model broken (1)

tonywestonuk (261622) | about a year and a half ago | (#43800693)

Oh, once you've read it, if you can code, go try making a program to simulate whats going on.... Try it. At some point you'll come to the conclusion that something really weird is happening.

Re:Photon model broken (2)

Nefarious Wheel (628136) | about a year and a half ago | (#43800841)

Entangled Object Oriented language? Certainly you'd need parameter overloading.

Re:Photon model broken (1)

Anonymous Coward | about a year and a half ago | (#43800737)

I've wondered if quantization is an effect of measurable interactions by necessity using the same amount of energy implied by, in say the case of a photon, the its frequency. Partial photons would be able to explain a lot about quantum physics without resorting to multiple worlds theorem or people yelling "shut up Copenhagen works fine because I don't understand what's wrong with it!" I mean, even something as basic as the double slit/single photon experiment becomes easy to understand, the "photon" is split into two waves which interfere with each other, done.

Always good to see others thinking along the same lines.

Science (5, Funny)

MyLongNickName (822545) | about a year and a half ago | (#43800219)

At some point, science just got too weird. We had this nice model of the universe with atoms, some laws of motion and thermodynamics. The universe was basically a giant billiards match. It made sense. It was easy to explain. Then we get into quantum mechanics and everything is crap shoot. Multiple universes. Particles that behave differently when being observed. Spooky action at a distance.

Let's all pretend the last 80+ years of science didn't happen and we live under Newton's ideas of how everything behaved. Who's in?

Re:Science (2, Insightful)

Nyder (754090) | about a year and a half ago | (#43800297)

...

Let's all pretend the last 80+ years of science didn't happen and we live under Newton's ideas of how everything behaved. Who's in?

I'm sure some of the various religions will be glad to join your thinking (if they aren't already there).

Re:Science (4, Funny)

VortexCortex (1117377) | about a year and a half ago | (#43800315)

At some point, science just got too weird. We had this nice model of the universe with atoms, some laws of motion and thermodynamics. The universe was basically a giant billiards match. It made sense. It was easy to explain. Then we get into quantum mechanics and everything is crap shoot. Multiple universes. Particles that behave differently when being observed. Spooky action at a distance.

Let's all pretend the last 80+ years of science didn't happen and we live under Newton's ideas of how everything behaved. Who's in?

That's what you said last time. Look what it got us? We're back to quantum physics AND we have nuclear weapons. Are you really ready to risk Universe hopping again?

Re:Science (5, Funny)

Anonymous Coward | about a year and a half ago | (#43800323)

Nature and nature's laws lay hid in night;
God said "Let Newton be" and all was light.
It could not last; the Devil shouting "Ho!
Let Heisenberg be!" restored the status quo.

Re:Science (1)

louzer (1006689) | about a year and a half ago | (#43800327)

When history of these times are written scientists of quantum mechanics today would be considered like the scientists of planetary epicycles and scientists of Descartian physics.. There will be a simpler causal interpretation of the evidence which supports quantum mechanics without all the magic: De Broglie–Bohm theory.

Re:Science (4, Interesting)

Black Parrot (19622) | about a year and a half ago | (#43800383)

The latest Scientific American has an article about a newish bayesianized quantum theory. To the limited extent that I understand it, the wave function is just the bayesian priors - what you think before you collect the evidence. The only thing that collapses when you measure something is your ignorance about the state of the universe.

Re:Science (1)

maxwell demon (590494) | about a year and a half ago | (#43800641)

Actually de Broglie-Bohms unobservable particle trajectories are the exact equivalent to the epicycles: Additional complications, introduced to save certain assumptions on the world (epicycles: only circular motion, with the earth in the center; Bohm trajectories: movement of well-localized particles in space).

Also, de Broglie-Bohm is incompatible with special relativity.

Re:Science (0)

Anonymous Coward | about a year and a half ago | (#43800691)

What makes you think so?

We have models for how things work. Little formulas that give the correct answer within a certain range of conditions, but don't represent the fullness of what's going on. That's normal and easily understandable, right?

But all of our senses, and for that matter our minds, evolved to catch deer and dodge tigers. And so they create this mental model of the world around us, and we arrogantly assume that that model is complete and shows the world as it really is. Time goes this way, things are exactly one place at each moment, etc. It's a useful model, and I'm certainly not suggesting we abandon it (as if such a thing is even possible). But it's silly to think that the universe just so happens to work in a way that our brains would find intuitive or simple.

Re:Science (1)

Anonymous Coward | about a year and a half ago | (#43800375)

At some point, science just got too weird. We had this nice model of the universe with atoms, some laws of motion and thermodynamics. The universe was basically a giant billiards match. It made sense. It was easy to explain. Then we get into quantum mechanics and everything is crap shoot. Multiple universes. Particles that behave differently when being observed. Spooky action at a distance.

There is no such thing as "observation". The universe completely lacks a "read" operation.

What we think of observation is *always* upon on closer inspection interaction. Any concievable measuring device or method of observation functions by disrupting its environment. e.g your eyes don't "see" they absorb photons produced or reflected by surfaces.

Spooky correlated behaviors are just a particular transaction semantic.

Re:Science (0)

Anonymous Coward | about a year and a half ago | (#43800411)

Then I guess you can go back to vacuum-tube-powered computing? The humble solid-state diode and transistor are based on quantum physics (though the common derivation uses a "quasi-classical" simplification to make the math tractable) even in the "classical" computers since the 1960s.

Even there, though, and you're only down to the era of Maxwell, not Newton. If you want to return to Newton's ideas, you need to crank up a Babbage machine!

Re:Science (1)

Anonymous Coward | about a year and a half ago | (#43800415)

Particles that behave differently when being observed.

This is much easier to understand when you realize that our "observations" of quantum events is less like looking at something, and more like poking it with a stick.

No Science, No Porn (2)

ikaruga (2725453) | about a year and a half ago | (#43800509)

Without quantum physics the cameras, fast CPU, GPUs and high speed communications that help me cope with my solitude at night wouldn't exist. Count me out brah.

Re:Science (4, Funny)

fightinfilipino (1449273) | about a year and a half ago | (#43800567)

Let's all pretend the last 80+ years of science didn't happen and we live under Newton's ideas of how everything behaved. Who's in?

the Republican Party? large swaths of the American Bible Belt? Scientologists? Liberal Arts majors? Michio Kaku?

Re: Science (0)

Anonymous Coward | about a year and a half ago | (#43800581)

Sounds Great

posted from my iTelephone

Re:Science (0)

Anonymous Coward | about a year and a half ago | (#43800651)

Who's in?

I'm in.

...Well, I think I am, but thanks to quantum physics I might actually be out (tunneling), or even both in and out at the same time (superposition). So maybe asking me isn't the best option.

You could to ask my friends what they think (complementarity) because I'm sure they all know me well enough to say (wave functions). Oh, but while they could tell you where I am, they wouldn't know if I might just up and change my mind (uncertainty principle).

Re:Science (0)

Anonymous Coward | about a year and a half ago | (#43800755)

fuck yes, I'm in.

"doesn't exist" (4, Funny)

girlintraining (1395911) | about a year and a half ago | (#43800227)

Hey guys, Einstein just called me using GravePhone(tm) and he had the following to say:

"Okay, maybe God does play dice, but I still stand by the law of conservation. God doesn't just make shit up. Now if you'll excuse me, Aristotle wants some one on one on the basketball court."

Measurement error (1)

PedroV100 (1497409) | about a year and a half ago | (#43800273)

This is probably a measurement error that the media will make sure to overhype again. I wonder how many paradoxes you can create if it were true. Cats can prey on the grandparents of the scientists of the future before the scientists are conceived. Yet these scientists may have the control over the cat's life/death before the cat has the chance to kill anyone.

Re:Measurement error (-1)

Anonymous Coward | about a year and a half ago | (#43800303)

how retarded are you?

Re:Measurement error (1)

Anonymous Coward | about a year and a half ago | (#43800329)

The problem is that entanglement doesn't actually allow you to send information anywhere using it. It does weird things, but you can't actually cause one particle to change state the way you want it to. Trying to alter the state breaks the entanglement. So there is no violation of the principle that information can travel faster than light, or backwards in time.

It is useful in quantum communication as a source of shared randomness, because the states are shared in a known way, but I can't control the state of the particles.

Re:Measurement error (1)

maxwell demon (590494) | about a year and a half ago | (#43800665)

No, it's not a measurement error. It's exactly what you'd expect from such a setup, without assuming entanglement over time. However, if they had described this experiment as what it actually is, a standard Bell measurement where one of the photons was quantum-teleported before measuring it, but after having measured the other photon, I'm sure it would not have generated much interest.

Re:Measurement error (1)

maxwell demon (590494) | about a year and a half ago | (#43800707)

Oops, I just notice I mixed up the terminology: It's of course not a Bell measurement (although a Bell measurement is involved in the teleportation/"entanglement swapping" step), but the measurement of a Bell inequality violation.

I can has closed time loops? (1)

Anonymous Coward | about a year and a half ago | (#43800295)

Can we use this trick to create closed time loops?

B sends message to A using ordinary speed-of-light (or even speed-of-sound) communications.
A sends the message back in time to B, via entangled photons, since B can measure his photon before A's photon ever existed.

Plot twist: B never told A that the original message came from the entangled photon experiment, and A never told B that his message came from B.
How is mesagge fromed?

Re:I can has closed time loops? (1)

Black Parrot (19622) | about a year and a half ago | (#43800391)

Why not just take a little piece of paper, and write "see other side" on both sides?

Re:I can has closed time loops? (0)

Anonymous Coward | about a year and a half ago | (#43800399)

Because that's just a "time waster"; it's not related to the time loop paradox that creates information from nothing.

Re:I can has closed time loops? (1)

maxwell demon (590494) | about a year and a half ago | (#43800675)

Can we use this trick to create closed time loops?

No.

B sends message to A using ordinary speed-of-light (or even speed-of-sound) communications.

OK, no problem in this step. ;-)

A sends the message back in time to B, via entangled photons, since B can measure his photon before A's photon ever existed.

No. You cannot send a message just using entangled photons. You always have to send classical information along in order to communicate. So to use entanglement for sending information into the past, you'll first have to solve the problem of sending classical information into the past.

Think of the entangled photons as being an encryption key. It doesn't help you if you get the encryption key, as long as you don't also get the encrypted message.

Re:I can has closed time loops? (0)

Anonymous Coward | about a year and a half ago | (#43800717)

No problem. Transmit a message of all zeros. Now the decryption key is the message.

Makes sense enough (1)

erichill (583191) | about a year and a half ago | (#43800321)

It looks like quantum teleportation meets delayed choice.

Getting so tired of this "instantaneous" BS (5, Interesting)

quax (19371) | about a year and a half ago | (#43800341)

Special Relativity makes quite clear that if two particles are spacelike [wikipedia.org] separated when measured, that the concept of "instantaneous" is devoid of meaning.

If you have this kind of distance than you will have just one special reference frame where this is true, and infinite more where the events are arbitrarily separated in time. This is already at the core of the EPR paradox [wikipedia.org] .

I.e. that you can have entanglement across time follows trivially from SR and the EPR paradox.

It's just astounding how many times the very same insight can get repackaged and sold as new.

Re:Getting so tired of this "instantaneous" BS (5, Funny)

avgjoe62 (558860) | about a year and a half ago | (#43800377)

It's just astounding how many times the very same insight can get repackaged and sold as new.

And that my son is why you will never work for the patent office.

Re:Getting so tired of this "instantaneous" BS (1)

RevWaldo (1186281) | about a year and a half ago | (#43800549)

Einstein worked at the patent office. Just sayin'.

.

Re:Getting so tired of this "instantaneous" BS (1)

Lord Maud'Dib (611577) | about a year and a half ago | (#43800657)

Whoosh!

Re:Getting so tired of this "instantaneous" BS (3, Insightful)

quax (19371) | about a year and a half ago | (#43800429)

It's a common misconception that QM as a theory of the microcosm is somehow more general and accurate than SR. Yet, the derivation of SR does not even require the constance of light speed (although that's the route that Einstein oribinally followed), but can be derived from very obvious first principles [ist.utl.pt] .

And this is a key difference to QM where this still hasn't been accomplished (despite the theory being such a fantastic empirical success story). Of course as far as empirical evidence goes SR also has a spotless record (which is why the CERN faster than light brewhaha was pretty much a forgone conclusion [wavewatching.net] ).

.

 

Re:Getting so tired of this "instantaneous" BS (1)

jouassou (1854178) | about a year and a half ago | (#43800713)

Thanks for the link to the SR paper! It was a fascinating read :).

Re:Getting so tired of this "instantaneous" BS (1)

maxwell demon (590494) | about a year and a half ago | (#43800797)

If you look at the paper closely, you'll see that it derives that under the given assumptions you get either SR (Lorentz transformation) or Newtonian space and time (Galilei transformations). The fact that he terms Galilei symmetry as degenerate Lorentz symmetry (which is mathematically true) doesn't change the fact that this argument doesn't decide between the two options. It only excludes that there's a third option.

Re:Getting so tired of this "instantaneous" BS (1)

c0lo (1497653) | about a year and a half ago | (#43800617)

Special Relativity makes quite clear that if two particles are spacelike [wikipedia.org] separated when measured, that the concept of "instantaneous" is devoid of meaning.

If you have this kind of distance than you will have just one special reference frame where this is true, and infinite more where the events are arbitrarily separated in time.

While the above is true, I wonder how is this relevant to the issue at hand?
I mean: who the hell mentioned something about instantaneous?

TFA:

to begin, researchers zap a special crystal with laser light a couple of times to create two entangled pairs of photons, pair 1 and 2 and pair 3 and 4.

1. First zap - they create (1,2)
2. Next zap (delta(t)>0) in the same space (delta(r)==0): they create (3,4)
Seems to me they are working in time-like conditions [wikipedia.org] , aren't they?

The experiment shows that it's not strictly logical to think of entanglement as a tangible physical property, Eisenberg says. "There is no moment in time in which the two photons coexist," he says, "so you cannot say that the system is entangled at this or that moment." Yet, the phenomenon definitely exists.

My first read of TFA: the guys managed to "entangle" photons created at different times.
But then... hang on... weirder-and-weirder : they entangled photons that don't even exist in the same time.

In any case, certainly nothing to do with "instantaneous" BS, quite the contrary!

Re:Getting so tired of this "instantaneous" BS (0)

Anonymous Coward | about a year and a half ago | (#43800685)

who the hell mentioned something about instantaneous?

The summary did: "Physicists have long known that quantum mechanics allows for a subtle connection between quantum particles called entanglement, in which measuring one particle can instantly set the otherwise uncertain condition, or 'state,' of another particle—even if it's light years away."

Re:Getting so tired of this "instantaneous" BS (0)

Anonymous Coward | about a year and a half ago | (#43800721)

Special Relativity makes quite clear that ...

There is no way to end that sentence truthfully.

Re:Getting so tired of this "instantaneous" BS (1)

jouassou (1854178) | about a year and a half ago | (#43800805)

Special Relativity makes quite clear that if two particles are spacelike separated when measured, that the concept of "instantaneous" is devoid of meaning.

From TFA:

Eisenberg emphasizes that even though in relativity, time measured differently by observers traveling at different speeds, no observer would ever see the two photons as coexisting.

So the separation was timelike, not spacelike.

Yes I knew it! (1)

can.you.feel.my.808 (1322153) | about a year and a half ago | (#43800357)

Timeline really iiiis real!

What is true on a micro scale (-1)

Anonymous Coward | about a year and a half ago | (#43800389)

is always true on a macro scale

think about this long and hard folks.

Here's another theory for you (2)

NewtonsLaw (409638) | about a year and a half ago | (#43800467)

Some time ago I gave some thought to the apparent anomalies and strangeness of the quantum world.

Here's what I came up with as a theory It's all about time [aardvark.co.nz]

Comments would be welcomed from all the (real and wannabe) quantum physicists out there.

The summary makes a bigger deal of this than it is (4, Informative)

Y.A.A.P. (1252040) | about a year and a half ago | (#43800485)

When you read the article, this isn't actually too controversial. All that's being done is changing the timing of of when the measurements are taken and when the intermediate photons become entangled. It's really just using the entanglement process to spread out the time over which the quantum state data is transmitted. You basically have a quantum data historical record.

I can certainly see this opening up useful new capabilities in quantum computing and measurement of quantum phenomena, but it doesn't change our understanding of quantum events and how they interact with our "everyday notions of space and time.".

Slower than the speed of light (1)

XNormal (8617) | about a year and a half ago | (#43800487)

Superposition, wave function collapse and other quantum effects are supposed to govern everything. But I don't seem to recall any such weird experiments that do not involve any particle traveling slower than the speed of light.

Are there any such demonstrations that involve only interactions between particles having nonzero rest mass?

Re:Slower than the speed of light (1)

wonkey_monkey (2592601) | about a year and a half ago | (#43800847)

The double-slit experiment can be done with electrons and atoms.

Things that go bump in the night... (-1, Troll)

flyingfsck (986395) | about a year and a half ago | (#43800637)

Things that don't exist are a very important part of Israeli culture, but it is not science.

There's nothing more slippery than an Israeli. (0)

Anonymous Coward | about a year and a half ago | (#43800727)

No doubt they will try to find a way to use this to further extort money and military aid from their "friends."

42? (1)

future assassin (639396) | about a year and a half ago | (#43800775)

????

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