(Possible FTL Advancement!)NASA Researchers Put New Spin On Einstein's Relativity Theory

Science Daily ^ | 2003-04-10 | Editorial Staff

[vannrox]

NASA Researchers Put New Spin On Einstein's Relativity Theory

Albert Einstein might be astonished to learn that NASA physicists have applied his relativity theory to a concept he introduced but later disliked namely that two particles that interact could maintain a connection even if separated by a vast distance. Researchers often refer to this connection as "entanglement."

Researchers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., have discovered that this entanglement is relative, depending on how fast an observer moves with respect to the particles, and that entanglement can be created or destroyed just by relative motion. This might change the way entanglement is used on future spacecraft that move with respect to Earth or with each other.

"Imagine a particle on Earth entangled with a particle light years away," said Dr. Christoph Adami, principal scientist in the Quantum Computing Technologies Group at JPL. "Whatever happens to particle A on Earth happens to particle B, even if it is on another planet. Einstein referred to this connection as 'spooky'."

Einstein thought this connection violated the relativity rule that information can't travel faster than the speed of light. Adami and Dr. Robert Gingrich, also of JPL, are the first to apply Einstein's relativity theory to quantum entanglement between particles. They compared the amount of entanglement when the particles were at rest to when they were given a boost. Their findings show that while speeding up ordinary entangled pairs would lead to a loss of the precious entanglement, certain special pairs can be created whose entanglement is increased instead. This increases the connection between them.

Understanding how some of the characteristics of a particle can become entangled through relative motion alone when they seemed to be unentangled or unconnected when at rest could have many applications. For example, entangled particles could be used to synchronize atomic clocks, which are essential for navigating spacecraft in deep space.

"One of the amazing things about entanglement is that it connects objects over arbitrary distances, so that in principle the two clocks could be started and stopped simply by acting on only one of them," said Adami.

"However, no workable protocol has been found to date to achieve that."

Because the creation of entanglement in the laboratory is usually a delicate matter, discovering new ways to create entanglement is always a goal of the quantum technology community.

"If you can create entanglement just by moving with respect to what you're measuring, then seemingly you've created something from nothing," said Gingrich.

Another possible application of entanglement is quantum teleportation: the ability to transfer the precise quantum state of one microscopic object to another, while using only traditional communications, such as a phone line. This technique, which has been demonstrated experimentally, requires that the sender and receiver share pairs of entangled particles. But until now nobody knew what would happen to these pairs if the sender and receiver move with respect to each other, or if an observer moves with respect to them. This new theory gives researchers a whole new outlook on what happens to particle pairs when you apply the relativity theory.

The research also has ramifications for ongoing work in the area of quantum computation, which seeks to use the subtle effects of quantum mechanics to build faster and more efficient computers.

"Whenever new ground is treaded by theory, new applications are sure to follow in its wake," said Adami. Gingrich and Adami's findings appeared in a paper they co-authored titled, "Quantum Entanglement of Moving Bodies," which appeared in the December 2002 issue of the journal Physical Review Letters.

The Quantum Computing Technologies Group at JPL investigates the design and capabilities of hypothetical computing and measurement devices that use delicate quantum effects for enhanced power and accuracy for future space missions.

More information is available at

http://cs.jpl.nasa.gov/qct/qat.html.

NASA's Office of Earth Science, Washington, D.C. provided funding for this work. The California Institute of Technology in Pasadena manages JPL for NASA.

Editor's Note: The original news release can be found here.

Note: This story has been adapted from a news release issued for journalists and other members of the public. If you wish to quote any part of this story, please credit NASA's Jet Propulsion Laboratory as the original source. You may also wish to include the following link in any citation:

http://www.sciencedaily.com/releases/2003/04/030410073215.htm

[Doc On The Bay]

1965 IS NOT 2003!

'Hold you're Hats,!"--- "BIG STUFF IS COMING!!"

[Erasmus]

>>Possible FTL Advancement!

>Application to underwear? Highly advanced underwear.

>This could be hugh! I'm very series!

Nuttin' but the best!

[coloradan]

I would have to see the article, but I doubt they did what you think they did. You can alter what property of a photon you are trying to measure in the fly, but no matter what you do actually measure, you then know what the other photon will give when this same property is measured. But you didn't choose what your photon will yield, so you can't send this information FTL to the receiver of the other photon.

[#3Fan]

Yeah, I'll have to look for it to see exactly how they affected it. They may have just absorbed it into the sensor. When I have time to look for that issue, I'll get back to you. It may be a few days or weeks. I'll save this thread.

[#3Fan]

Here's something I found from here:

When two photons are split apart from a single photon mother, they are connately linked by an inseparable quantum bridge. Quantum theory, backed up by the most current experiments, suggests that this bond is so close, that manipulating one photon of an entangled pair causes the same result to occur on the other photon, even if it is across the lab bench or at the other end of the universe (Brooks, 1999. Buchanan 1999. Turchette et al 1998).

They just say "manipulate". hmmm.

[coloradan]

Hmmm indeed. If you pass one photon through a polarizing beam splitter, for example, you "manipulate" it. And the port the photon decides to go through dictates which port the other will also go through. (Usually for entangled pairs, it's the other port.) The text you quoted sounds like you can force some sort of outcome upon your own photon, which forces an outcome on the other. But I don't think that's correct. The text is also consistent with my own understanding that you can observe the outcome of your own photon, whatever it may be, and then know what the other one will give. In the former case you could send FTL info, in the latter you can not. I can't tell from the quote which case they are talking about.

[#3Fan]

Ok, I found the Discover article here. (I figured I'd check the internet before I went rummaging through my back-issues. It's a good thing...it was five years ago, not 2 or 3, I wouldn't have found it. I can't believe it's been five years since I read that article!...:^)...)

It says it was seven miles apart, not two, and in Geneva. I'll post it in my next post.

[#3Fan]

Score one (more) for the spooks. (quantum mechanics and particle research)(The Year in Science: 1997)(Brief Article)
Author/s: Robert Pool
Issue: Jan, 1998

Einstein would not have been amused. Not only did researchers demonstrate last May a phenomenon that the Great One once disparaged as "spooky action at a distance," but they proved it happens even at great distances. Worse, they performed the experiment in Switzerland, not far from the patent office where Einstein worked in 1905 -- the year he explained the quantum nature of light, which laid the foundation for quantum mechanics, which he later found so maddeningly spooky.

The spooky action in question involves a voodoolike link between two particles such that a measurement carried out on one has an instantaneous effect on the other, though it be far away -- nearly seven miles away, in the experiment done by physicist Nicolas Gisin's team at the University of Geneva. Gisin and his colleagues borrowed fiber-optic phone lines running from Geneva to two nearby villages. In Geneva, they shone photons into a potassium-niobate crystal, which split each photon into a pair of less energetic photons traveling m opposite directions -- one north toward Bellevue and the other southwest to Bernex. At these two destinations, nearly seven miles apart, each photon was fed into a detector.

Common sense would suggest that nothing done to the photon in Bellevue could affect the photon in Bernex, or vice versa, but quantum mechanics never had much to do with common sense. For starters, the uncertainty principle says that Gisin cannot simultaneously know both the energy of a photon and the time it left the crystal in Geneva, at least not precisely. Furthermore, quantum mechanics insists that the photons don't have precise properties until they are measured. To show what he saw as the absurdity of the claim, Einstein proposed a simple thought experiment in 1935, and this became the basis for Gisin's complicated real one.

Einstein believed that the uncertainty principle was just a measurement problem, not a reality problem. His idea, in terms of the Geneva experiment, was that you could learn the energy of one photon by measuring the energy of the other one far away; by the same token, you could learn a photon's arrival time by measuring that of its distant counterpart. After all, the two photons had to leave Geneva at the same time, and although their energies might not be equal, they have to add up to the energy of the parent photon. Assuming that these measurements could be made, and that they added up in this commonsense way, Einstein would be correct, and reality would be independent of measurement. Or you'd be forced to argue that the Bellevue measurement instantaneously and spookily changes the reality of the photon at Bernex, which to Einstein was an absurd suggestion.

The mind game itself was proof enough for Einstein, but in 1964 physicist John Bell turned it into a testable hypothesis. He came up with an equation, called Bell's inequality, that boiled the question down to a set of measurements of many photons hitting detectors. If energy and arrival time were absolute values, as Einstein believed, then these measurements would be true to Bell's inequality. If, on the other hand, quantum mechanics was valid after all, and the precise energy and arrival time of a photon did not exist until they were measured, the measurements would violate Bell's inequality

In Gisin's experiment, alas, Einstein and common sense were the losers. It's as if he had flipped a coin at Bellevue, Gisin says, while his colleague had flipped one at Bernex, and each time he grabbed his coin out of the air and saw it was heads up, his colleague's coin had simultaneously stopped spinning and landed heads up as well. And this happened thousands of times in a row. "It is a very strange prediction," Gisin says, "and because it is so bizarre, it deserved to be tested."

In fact, it had already been tested many times, most notably in 1981 when physicist Alain Aspect from the University of Paris first dazzled his peers by demonstrating the phenomenon. But Aspect separated his photons by only a few meters, and since then some physicists who share Einstein's reluctance to abandon common sense had speculated that the spooky effect might decline with distance. "We have now done it in the lab, and we have done it at 10 kilometers, and we found no significant differences," Gisin says. Common sense, at least in the quantum world, would seem to be a dead horse -- but Gisin is planning one more crack at the corpse. He wants to set up a test at an even farther distance -- perhaps the 60 miles that separate Geneva and Bern, the site of the patent office where Einstein worked. He even knows when he wants to do it: in 2005, the centennial of Einstein's pioneering paper.

COPYRIGHT 1998 Discover

COPYRIGHT 2000 Gale Group

[#3Fan]

It looks like the article is consistent with what you said. But maybe you could time the measurements to send like a morse code or something. Don't know.

[coloradan]

Thanks for the post.

But it confirms my opinion:

It's as if he had flipped a coin at Bellevue, Gisin says, while his colleague had flipped one at Bernex, and each time he grabbed his coin out of the air and saw it was heads up, his colleague's coin had simultaneously stopped spinning and landed heads up as well.

So, as soon as you know your coin is heads, you know the other one will be heads too. But you can't force your coin to come up heads on any given trial (therefore, sending a bit "1," say) and therefore force the other one to be received as heads. You can't use this to send an arbitrary bit sequence, you only know what random bits they will get. For example, you can't force your coin to come up as ten heads in a row, forcing the other station to receive ten heads in a row as well.

And yes, this was the story I remember, except that it was Switzerland and not Germany.

[#3Fan]

Yeah, I bet they find a way around it. If they can see which way the photon "flipped" FTL, then I think they'll be able to manipulate a message eventually.

[coloradan]

No, you can't time when you receive the photons; they are created randomly at some rate in the crystal, and when you get one the other station gets one. Imagine a fountain that sends out entangled water droplets. When one lands on your head, one lands at exactly the same time on the other guy's head, standing across the fountain, and both you and he know this. But you can't cause the ones hitting you to arrive in a specific time sequence on your head, thus you can't "send" a code of similar arrival times FTL to the other guy.

[newguy357]

Most of which cannot be inhabited because they're within radiation belts....

[coloradan]

Yeah, I bet they find a way around it.

I bet they won't.

If they can see which way the photon "flipped" FTL, then I think they'll be able to manipulate a message eventually

Begs the question. If they can see FTL, then they can certainly send FTL - you just have two people looking at each other with FTL portals: Give them each chalkboards. One guy writes something on his board, and the other one immediately sees it FTL through the portal. The other guy can then write a reply and the first sees it FTL.

But I believe the portal is impossible.

[RightWhale]

the most you can do is change the random sequence your counterpart on the moon is seeing to a DIFFERENT random sequence, but it will still look random to him.

The observed state is polarization. Another experiment has shown it is not necessary to destroy the receiving photon in order to read it. This phenomenon may turn out be useful.

[JoeSchem]

"However, no workable protocol has been found to date to achieve that."

Key sentence.

[#3Fan]

Looks like you'd have to check the state of the photon without absorbing it. Perhaps a Bose-Einstein condensate (BEC). If the message receiver could see the moment the entangled photon locked into a state, then the message sender could just time the moment he measured his to send a message. It may not be possible for the BEC to record the state of the photon as it absorbs it and re-emits it without losing the entanglement though, I don't know. Or perhaps the BEC doesn't store the values of the photons after they're emitted, I don't know that either.

I don't think there would be a situation of time travel, it's just a matter of perceiving real-time.

[#3Fan]

The observed state is polarization. Another experiment has shown it is not necessary to destroy the receiving photon in order to read it. This phenomenon may turn out be useful.

Was the "another experiment" you spoke of the BEC (Bose-Einstein condensate) experiments?

[Timesink]

The hitch: The tachyons in your body "entangled" with tachyons at the other end, and it was really a sort of "clone" of you that showed up at the other end.

I've often wondered how anyone on Star Trek knows that they're not just getting killed and cloned every time they step into a regular transporter.

[I_dmc]

Hmm. What is thought? I've always believed that communication via thought was instantaneous, regardless of distance.