Quantum Network in Orbit!

[YourEverydayWaffle]

This is really cool. A team of physicists are working on what they say is going to be the most precise "clock" ever. So, their plan is to send many of these quantum clocks up into orbit. The clocks will then prepare entangled particles (for those of you who don't know, entangled particles [usually photons] are particles that are... well, entangled. If one particle is observed [presumably in a superposition before the observation] to have a certain spin, then the other particle in the entangled pair will have it's spin relative to that. It isn't always opposite or the same, but if one particle changes, the other will change based on that change as well. Entangled particles can be used as a data link, as some Dutch scientists just managed to do, that can "communicate" at roughly 10000 times the speed of light, which, for all human perception is concerned, is instantaneous.). The clocks will form a link using these particles and will become a sort of "quantum network". If only we could do more with entanglement; it's just too fragile of a state. That's why quantum computing is out of our reach at the moment. On the other hand, quantum entanglement has shown effects after breaking, too (not entirely sure what, though), and quantum physicist Seth Lloyd suggests did some of his own research that brings to mind that if one were to make a camera that filters out all photons except for the photons that have had their entanglement broken, it could open up possibilities of camera flashes and sensors that use this, and therefore would eliminate all unwanted background light that can generate fuzz. We're finally bridging into quantum data and similar things. Pretty awesome.

Edited June 23, 2014 by YourEverydayWaffle
Specified more on the camera.

[the_bT]

I admit to being under-informed on quantum physics, but how does the ability to communicate information at such high speeds improve the precision of a clock?

Even if its just the imprecision you get when a time synch signal is transmitted and received with a delay... That can be averted by using multiple signals from different sources like for example the GPS system does.

So, can anyone enlighten me?

Edit: or is it intended for communication and the term clock is just an allegory?

[N_las]

Can you please link to the paper that describes a communication faster than the speed of light. Entangled Particles shouldn't be able to transmit information.

Edit: And whats up with "people say... ". It is hard to discuss a scientific topic if all we have is the distorted view of someone based on hearsay.

Where did you read that "entangled particles show a connection even after breaking the entanglement". Where did you read about the camera?

Edited June 23, 2014 by N_las

[YourEverydayWaffle]

I admit to being under-informed on quantum physics, but how does the ability to communicate information at such high speeds improve the precision of a clock?

Even if its just the imprecision you get when a time synch signal is transmitted and received with a delay... That can be averted by using multiple signals from different sources like for example the GPS system does.

So, can anyone enlighten me?

Edit: or is it intended for communication and the term clock is just an allegory?

I believe the purpose is merely for accuracy. I forgot to mention that these clocks are atomic clocks, as well, so it is pretty much a network of incredibly accurate clocks linked together to (presumably) form an average of their data at incredibly fast speeds, thanks to the entanglement link. So, if one clock has an error of a microsecond or two, it will be quickly leveled out using the link. The reason they use entanglement is because at the accuracy of these atomic clocks, speed-of-light communication (radio waves and other light-based com systems) just won't do. The high speed communication improves the accuracy of the clock as a whole system.

EDIT: http://www.scientificamerican.com/article/quantum-entanglement/

I'm not great with phrasing things, so "people say" is my way of saying that something has been speculated in whatever way. Sorry about that.

I should also rephrase the line where that was: quantum physicist Seth Lloyd said that [camera info] is also a possibility for future development.

Edited June 23, 2014 by YourEverydayWaffle

[YourEverydayWaffle]

Can you please link to the paper that describes a communication faster than the speed of light.

Issue with entanglement is that we know so little about it, we can't really be sure of anything other than the observable results. I believe the furthest entanglement test was 144 kilometers. As far as people can tell, it is far faster that any light based communication we know of today. The issue is that there is (as far as we can tell with today's technology) no observable "communication" (as in common transfer of some sort of particle or data, like with a radio link) between the two particles. So in those long-range tests, the particle-particle action happened quicker than if it was done with a wave of light. It's a pretty fuzzy area, so I would just suggest you Google "entanglement communication faster than light" and see what you find. It just all depends on your definition of communication. So, until scientists figure out what is really going on under the hood, it's safer to refer to entanglement like Einstein did: "Spooky action at a distance".

[Dodgey]

Ok but do you have a source of this information or are we just taking your word for it.

[N_las]

Issue with entanglement is that we know so little about it, we can't really be sure of anything other than the observable results. I believe the furthest entanglement test was 144 kilometers. As far as people can tell, it is far faster that any light based communication we know of today. The issue is that there is (as far as we can tell with today's technology) no observable "communication" (as in common transfer of some sort of particle or data, like with a radio link) between the two particles. So in those long-range tests, the particle-particle action happened quicker than if it was done with a wave of light. It's a pretty fuzzy area, so I would just suggest you Google "entanglement communication faster than light" and see what you find. It just all depends on your definition of communication. So, until scientists figure out what is really going on under the hood, it's safer to refer to entanglement like Einstein did: "Spooky action at a distance".

[sgt_flyer]

You don't have to explain that to me. I had many courses on quantum mechanics at university. From my understanding, and from everything I every read about that topic, a faster than light communication using entangled particles isn't possible. You can't transmit information from one particle to the other simply by breaking the entanglement.

You claimed that dutch scientist have demonstrated a data link that was 10000 times faster than the speed of ligth, based on entanglement. Please link to the paper in question.

Besides even if it was possible to transmit infos by breaking the entaglement - you'll have a problem : how will you reestablish entanglement afterwards ? so your entangled pairs would be a 1 use thing - not really useful for data links.

[N_las]

Besides even if it was possible to transmit infos by breaking the entaglement - you'll have a problem : how will you reestablish entanglement afterwards ? so your entangled pairs would be a 1 use thing - not really useful for data links.

If that would be the problem, you could prepare an ensemble of quadrillions of entangled particle pairs. But you have to order a new package of "fresh" entangled particles every other day from Amazon.

[jfull]

Unfortunately, entangled particles CANNOT be used for communication. There's no "if"s or "maybe"s about it.

While information can be encoded into an entangled system, you need to be able to look at BOTH ENDS in order to extract that information, meaning that you're still restricted by the speed of light.

[YourEverydayWaffle]

If that would be the problem, you could prepare an ensemble of quadrillions of entangled particle pairs. But you have to order a new package of "fresh" entangled particles every other day from amazon.

I never said that the links involved breaking the entanglement. The entanglement is never voluntarily broken during communication. That was quantum physicist Seth Lloyd's theory about using such photons for high-res cameras. As for the speed of entanglement, it is very tough to tell whether its speed exceeds that of light. Some physicists say yes, others say no. The Dutch scientists weren't the ones to make the speed claim either; that was a team of physicists led by Juan Yin at the University of Science and Technology in Shangai. They were the ones who claimed that it happens at a base of 10000 times the speed of light.

Here are some sources:

Dutch Scientists' results

" " here as well.

Juan Yin's findings

Another paper by his team

The "10000" claim may have been made elsewhere than that paper, as well.

And for those of you who just want sources for entanglement:

TIME

Wikipedia

Sciencedaily

[N_las]

The quantum teleportation from your first and second source can't be used to transmit information faster than the speed of light. To establish a successful teleportation, classical communication is necessary: http://en.wikipedia.org/wiki/Quantum_teleportation

Your third source even says: "Whereas the result may sound like a way to send faster-than-light messages, it isn't, really, because you can't know the state of the entangled photon pair before it's measured"

There is no evidence in any of your sorces that suggest a faster-than-light data link.

EDIT:

I never said that the links involved breaking the entanglement. The entanglement is never voluntarily broken during communication.

To read the quantum state from the system, after a successful quantum teleportation, you have to break the entanglement.

Edited June 23, 2014 by N_las

[YourEverydayWaffle]

The quantum teleportation from your first and second source can't be used to transmit information faster than the speed of light. To establish a successful teleportation, classical communication is necessary: http://en.wikipedia.org/wiki/Quantum_teleportation

Your third source even says: "Whereas the result may sound like a way to send faster-than-light messages, it isn't, really, because you can't know the state of the entangled photon pair before it's measured"

There is no evidence in any of your sorces that suggest a faster-than-light data link.

To read the quantum state from the system, after a successful quantum teleportation, you have to break the entanglement.

I misunderstood what was asked: I did not realise you were talking about the observation of it's state. I assumed you were talking about the presumed change between the photons while in a superposition for the speed of communication as well. The 3 links at the bottom were also meant to show the other side of debate. I know I was a bit off in some things, but I did not intend to stir up this argument in talking about the clock system. The post was only meant to mention the new super-clock, and not argue about a field of physics that is constantly undergoing change.

[N_las]

I misunderstood what was asked: I did not realise you were talking about the observation of it's state. I assumed you were talking about the presumed change between the photons while in a superposition for the speed of communication as well. The 3 links at the bottom were also meant to show the other side of debate. I know I was a bit off in some things, but I did not intend to stir up this argument in talking about the clock system. The post was only meant to mention the new super-clock, and not argue about a field of physics that is constantly undergoing change.

Sorry, I didn't indent for this to be an argument. Quantum entanglement is interesting and quantum teleportation may be very useful for future communication applications. But it won't allow for faster than light communication.

[YourEverydayWaffle]

Sorry, I didn't indent for this to be an argument. Quantum entanglement is interesting and quantum teleportation may be very useful for future communication applications. But it won't allow for faster than light communication.

No worries, I learned a thing or two

[YNM]

A slight thing that clearly says that you can't communicate using quantum entanglement : No-communication theorem. Proven mathematically (or mathematical-physically), can't understand the equations through.

[YourEverydayWaffle]

A slight thing that clearly says that you can't communicate using quantum entanglement : No-communication theorem. Proven mathematically (or mathematical-physically), can't understand the equations through.

I've heard of this before. Sure hope those guys working on the clock system know what they're doing...

[YNM]

I've heard of this before. Sure hope those guys working on the clock system know what they're doing...

As long as they aren't trying to break the special relativity, then I guess it's fine... Entanglement just sorts of making everything appears equal (or neutralized).

[K^2]

It isn't always opposite or the same, but if one particle changes, the other will change based on that change as well.

Just to clarify, that's called maximally entangled state. There are other ways to entangle states.

Entangled particles can be used as a data link, as some Dutch scientists just managed to do, that can "communicate" at roughly 10000 times the speed of light, which, for all human perception is concerned, is instantaneous.

You can't communicate via entanglement. It's a useful "filter" for communications, but you are still limited to classical channels. So it's never faster than light. There are some FTL effects in QM, but they all have some very interesting limitations. Tunneling is a fantastic example of that.

Seth Lloyd suggests did some of his own research that brings to mind that if one were to make a camera that filters out all photons except for the photons that have had their entanglement broken, it could open up possibilities of camera flashes and sensors that use this, and therefore would eliminate all unwanted background light that can generate fuzz.

Yeah, that's doable. You need a laser that does quantum state amplification to preserve entanglement, and a bunch of other requirements, but the concept is great.

I've been looking into something similar in relation to communication and spectrum crunch. I have an algorithm that can do a 1000x "compression" using modern tech, and can be expanded up to 1Mx potentially. There are actually powerful enough solid state QCs to do rudimentary quantum information processing on a cell phone now. It's generating the signal that's the problem. So far, I've only figured out how to squish 400MHz worth of data into it, and you can do better than that with ordinary cell tower. I'm looking into EPR for an alt generator, though, which would bring me to 10¹² Hz, potentially. And then I just need a signal amplifier that can go in place of a conventional tower.

And yeah, it's all related to the concept of entanglement. Like I said, it doesn't let you communicate directly, but you can do awesome thing with a classical channel by throwing some entangled data at it.

As long as they aren't trying to break the special relativity, then I guess it's fine...

It's ok to break special relativity. It's already broken. What you should be careful with is general relativity. The difference is that in GR, the speed of light limit is local. What that means is that no signal can propagate faster than light relative to anything in its immediate neighborhood. QM gets around that limitation by having things not strictly speaking propagate. (Or, I should say, not propagate freely.) It's a tricky topic that I can get into with some examples, but it's all heavy on math.

Edited June 23, 2014 by K^2

[Skyler4856]

Or you could build a photon clock, and place it in a perfect vacuum/highly regulated atmosphere

[DaveofDefeat]

Atomic clocks...IN SPACEEEEEEEEEEEEEEE

[vger]

While information can be encoded into an entangled system, you need to be able to look at BOTH ENDS in order to extract that information, meaning that you're still restricted by the speed of light.

Why do you need to be able to look at both ends? Is this a Schrodinger's Cat phenomenon sort of like the double-slit uncertainty?

[K^2]

Why do you need to be able to look at both ends? Is this a Schrodinger's Cat phenomenon sort of like the double-slit uncertainty?

Because if you just make a measurement on your end, you can't possibly tell if what you measured was a state that has already been collapsed from the other end, or if you just collapsed it with your own measurement. And in the later case, the outcome is completely random. So you can't get any useful information out of it until you either look on the other side, or they send you a message with the results.

But if you did get measurements from the other end first, and then did the measurements and compared results, that's where magic happens. In a nut shell, that's how quantum teleportation happens. It's a little more complicated than that, all in all, but this was the basic idea that paved the way to the actual algorithm.

Edit: Just to clarify, if you just got results from the other end, and did the measurement with nothing in between, then you will just get a measurement that agrees with message that has been sent. The trick is to do the two measurements in different bases.