[Colin2B]

" That would mean there would be a theoretical means of detecting a signal  "

You're thinking of using different energy levels as a mean of communication? So do you know of any experiments taking into consideration the amount of energy injected in a measurement Collin?

What I'm saying is that the no signal theorem says such communication - using energy or anything else - is not possible. The spin experiment I described shows there is no energy transfer.
If you look at the QM descriptions of the particle states you will see that there is no suggestion that anything changes for the particles, just our knowledge of the states.

the reason is about how one should think of it, a entanglement as a 'indivisible particle' or as 'individuals' showing a correlation. In the first case 'injections' should 'transfer', in the other it's not necessary.

Not sure what you mean by 'indivisible particle'. QM says that the 2 particles are described by a single wavefunction, but that's not the same thing as an indivisible or connected particle. It is however, the same as 2, as yet unmeasured, particles showing a correlation.
As @alancalverd has said in the many worlds thread, the descriptions in QM are about how we handle probabilities and correlations.

[yor_on]

Which experiment are you referring to Collin? As far as I know the spin doesn't depend on the energy of a entanglement?

The last part goes back to a discussion I had with JP.
=

If you know of such a experiment and can link I would be pleased.
btw: that should tell you how long I've been wondering about it, me referring to JP :)

==

Heh :)
I'm lazy, I should have checked it up earlier, a lot earlier.

https://www.technologyreview.com/s/417362/physicist-discovers-how-to-teleport-energy/

Then again, it shouldn't be able to transmit information, just as you state. I'll need to look into that, and so do you I guess.

[Colin2B]

As far as I know the spin doesn't depend on the energy of a entanglement?

No, it doesn’t, but the measurement does cause a change of direction (momentum) of the measured electron (as I described in previous post) which is not reflected in the momentum of the other electron.

https://www.technologyreview.com/s/417362/physicist-discovers-how-to-teleport-energy/

You have to be careful regarding what is written in reports of experiments rather than what is written in the actual paper. I read this paper way back and read:
“Here it should be emphasized that this output energy existed not at A but at B even before the start of the protocol and was hidden in- side the zero-point fluctuation of B. Of course, this zero-point energy is not available by usual local operations for B. However, by using a local operation dependent on A’s information, it becomes possible to dig out B’s zero-point energy”
In other words, no energy is transmitted.

It is worth remembering that quantum teleportation is not a transfer of a particle from one place to another, but a duplication of the state of one particle imposed on another, using data transmitted over a classical link.

[yor_on]

Sure, I'm not saying that it it will be there just because a paper suggest a theoretical possibility. But what it say, as far as I've read, is that the injection adds 'energy' that wasn't there before, and that it will be this added energy that is lifted out.

" the process of teleportation involves making a measurement on each one an entangled pair of particles. He points out that the measurement on the first particle injects quantum energy into the system. He then shows that by carefully choosing the measurement to do on the second particle, it is possible to extract the original energy."

I told why I was interested , and that the idea of communication wasn't wherefrom I came to it. That seems to be your angle of attack on this,  but mine was just a question of it was possible to extract 'energy' from the injection of  energy done by a measurement.
=

But yes, you make a interesting point there. If now momentum isn't 'replicated', why should energy be so?
Let's assume that energy is 'replicated' but not momentum, what would be the reason?
Another question I'm afraid :)

And I suppose one would have to differ between light and mass when it comes to that. A added momentum to light should just blueshift it I think? But when it comes to a proper mass particle it should also be 'deflected' by the measurement, as you say.


Do you have a link to where that is tested Collin? Where they checked for it I mean?

[yor_on]

And I don't get where you get this 'classical link' in that paper, or maybe you're pointing out what both you and me actually agree on. That it shouldn't be possible to transmit useful information other than classically.  Seem's like we're talking of two different subjects.

[Colin2B]

And I don't get where you get this 'classical link' in that paper,

The classical link is standard for all quantum teleportation, it’s the way it works. It will be mentioned somewhere in the paper, but probably in passing. Remember, you are not transferring an electron from A to B, just duplicating the state of A to the state of B.
See this diagram:
https://en.m.wikipedia.org/wiki/File:Quantum_teleportation_diagram.PNG

I told why I was interested , and that the idea of communication wasn't wherefrom I came to it. That seems to be your angle of attack on this,  but mine was just a question of it was possible to extract 'energy' from the injection of  energy done by a measurement.

No, my angle isn’t to do with communication, but transfer of energy. As the paper points out, no energy is transferred from A to B.
Yes, the measurement extracts energy (at the remote location) that wasn’t accessible by other means. That’s what the paper says.

Do you have a link to where that is tested Collin? Where they checked for it I mean?

It is standard method for measurement of spin. Pass the electron through a mag field it deviates either N or S (up or down). Of course, if you rotate the magnets you get a different basis and different measurement which causes a lot of confusion for some people. Same happens with photon polarisation.

[yor_on]

Seems we have to agree on disagreeing here Collin, as far as I get you you define it as only (theoretically) extracting the energy of the 'second particle'? Or do you read it as it extract more that that, but not the injected energy?

When I read " As the paper points out, no energy is transferred from A to B.
Yes, the measurement extracts energy (at the remote location) that wasn’t accessible by other means. That’s what the paper says. "

then  I get confused?

If it only extract the energy of the 'second particle' without that particle having gained anything by being entangled the whole paper makes no sense. That's the energy of a untangled particle in such a case.

[yor_on]

And yes, forgot about that one, but have they measured the deviations?
=

And you keep referring to the standard classical approach for this paper? There is no stl (slower than light) information involved in it as far as I've seen?

[yor_on]

 " The relationship between energy and information has been investigated extensively in the context of computation energy cost including a modern analysis of Maxwell’s demon [1]-[2]. In this Letter, we show a new energy-information relation from a different point of view. Recently, it has been reported that energy can be transported by local operations and classical communication while retaining local energy conservation and without breaking causality [3]-[5]. Such protocols are called quantum energy teleportation (QET) and are based on ground-state entanglement of many-body quantum systems including spin chains [3], cold trapped ions [4] and quantum fields [5].

By performing a local measurement on a subsystem A of a many-body sys-tem in the ground state, information about the quantum fluctuation of A can be extracted. Because the post-measurement state is not the ground state in general, some amount of energy is infused into A as QET energy input during this measurement, and the ground-state entanglement gets partially broken. Next, the measurement result is announced to another subsystem B of the many-body system at a speed much faster than the diffusion velocity of the energy infused by the measurement. Soon after the information arrives at B, energy can be extracted from B as QET energy output by performing a local operation on B dependent on the announced measurement data. The root of the protocols is a correlation between the measurement information of A and the quantum fluctuation of B via the ground-state entanglement. Due to the correlation, we are able to estimate the quantum fluctuation of B based on the announced information from A and devise a strategy to control the fluctuation of B. By the above-mentioned selected local operation on B, the fluctuation of B can be more suppressed than that of the ground state, yielding negative energy density around B in the many-body system.

The concept of negative energy density has been investigated in quantum field theory for a long time [6]. Quantum interference among total energy eigenstates can produce various states containing regions of negative energy density, although the total energy remains nonnegative. The regions of negative energy density can appear in general many-body quantum systems by fixing the origin of the energy density such that the expectational value vanishes for the ground state. In spite of the emergence of negative energy density, the total energy also remains nonnegative for the general cases. In the QET protocols, during the generation of negative energy density at B, surplus positive energy is transferred from B to external systems and can be harnessed as the QET output energy. Here it should be emphasized that this output energy existed not at A but at B even before the start of the protocol and was hidden inside the zero-point fluctuation of B. Of course, this zero-point energy is not available by usual local operations for B.

However, by using a local operation dependent on A’s information, it becomes possible to dig out B’s zero-point energy by pair creation of the positive output energy from B and the negative energy of B. Hence, we do not need to hire any physical carrier of energy from A to B like electric currents and photons, at least, during short-time QET processes. Needless to say, after the completion of QET process, the positive energy of A compensates for the negative energy of B during late-time free evolution of the many-body system. The amount of output energy from B is upper bounded by the amount of input energy to A. "

[yor_on]

But it also seem to allow for a communication FTL?
Didn't think about that before you posted your objection Collin.
I'm not sure at all about this paper, but then again it's about that 'coin of exchange' as JP used to call it

 'energy'
=

From my own point of view It shouldn't be doable, if one gain a information protocol (FTL) by it. So if this works then there has to be something more involved in it, making it impossible to use as a information source.

[yor_on]

Although, thinking of it, all entanglements where you 'know' when to measure on the 'second particle' involves a slower than light arrangement, where you set a time for A and a time for B.  So there is always a 'classical conection' between the two, even if not measured on yet.
=

that is to say, to 'construct' a entanglement is to use classical information. Or better expressed, measuring on them getting a outcome, is a result of a prearranged construction and order of causality. And that one is still classical even if the opposite 'spins' found are instantaneous.

[Colin2B]

but have they measured the deviations?

Yes, should be in most textbooks. You get an eye diagram, one line above one below axis depending on whether up or down spin.

And you keep referring to the standard classical approach for this paper? There is no stl (slower than light) information involved in it as far as I've seen?

Classical means light speed or slower, not just stl.
Classical is mentioned right up front.
From paper:
“Abstract
Protocols of quantum energy teleportation (QET), while retaining causality and local energy conservation, enable the transportation of energy from a subsystem of a many-body quantum system to a distant subsystem by local operations and classical communication through ground-state entanglement. ........”

Look at the diagram I sent, it shows the classical data channel which is part of all teleportation experiments.

Seems we have to agree on disagreeing here Collin, as far as I get you you define it as only (theoretically) extracting the energy of the 'second particle'? Or do you read it as it extract more that that, but not the injected energy?

No, the paper says extract the same amount of energy at B as was input at A. I have highlighted in the quote you gave:

" The relationship between energy and information has been investigated extensively in the context of computation energy cost including a modern analysis of Maxwell’s demon [1]-[2]. In this Letter, we show a new energy-information relation from a different point of view. Recently, it has been reported that energy can be transported by local operations and classical communication while retaining local energy conservation and without breaking causality [3]-[5]. Such protocols are called quantum energy teleportation (QET) and are based on ground-state entanglement of many-body quantum systems including spin chains [3], cold trapped ions [4] and quantum fields [5].

By performing a local measurement on a subsystem A of a many-body sys-tem in the ground state, information about the quantum fluctuation of A can be extracted. Because the post-measurement state is not the ground state in general, some amount of energy is infused into A as QET energy input during this measurement, and the ground-state entanglement gets partially broken. Next, the measurement result is announced to another subsystem B of the many-body system at a speed much faster than the diffusion velocity of the energy infused by the measurement. Soon after the information arrives at B, energy can be extracted from B as QET energy output by performing a local operation on B dependent on the announced measurement data. The root of the protocols is a correlation between the measurement information of A and the quantum fluctuation of B via the ground-state entanglement. Due to the correlation, we are able to estimate the quantum fluctuation of B based on the announced information from A and devise a strategy to control the fluctuation of B. By the above-mentioned selected local operation on B, the fluctuation of B can be more suppressed than that of the ground state, yielding negative energy density around B in the many-body system.

The concept of negative energy density has been investigated in quantum field theory for a long time [6]. Quantum interference among total energy eigenstates can produce various states containing regions of negative energy density, although the total energy remains nonnegative. The regions of negative energy density can appear in general many-body quantum systems by fixing the origin of the energy density such that the expectational value vanishes for the ground state. In spite of the emergence of negative energy density, the total energy also remains nonnegative for the general cases. In the QET protocols, during the generation of negative energy density at B, surplus positive energy is transferred from B to external systems and can be harnessed as the QET output energy. Here it should be emphasized that this output energy existed not at A but at B even before the start of the protocol and was hidden inside the zero-point fluctuation of B. Of course, this zero-point energy is not available by usual local operations for B.

However, by using a local operation dependent on A’s information, it becomes possible to dig out B’s zero-point energy by pair creation of the positive output energy from B and the negative energy of B. Hence, we do not need to hire any physical carrier of energy from A to B like electric currents and photons, at least, during short-time QET processes. Needless to say, after the completion of QET process, the positive energy of A compensates for the negative energy of B during late-time free evolution of the many-body system. The amount of output energy from B is upper bounded by the amount of input energy to A. "

Remember, all you are doing is measuring the state of A, sending info about that to B so that you can operate on B and put it into the same state as A. See above where it says “by using a local operation dependent on A’s information, it becomes possible to dig out B’s zero-point energy”.

But it also seem to allow for a communication FTL?

I don’t see that it says that anywhere. Can you point it out?

Although, thinking of it, all entanglements where you 'know' when to measure on the 'second particle' involves a slower than light arrangement, where you set a time for A and a time for B.  So there is always a 'classical conection' between the two, even if not measured on yet.
=

that is to say, to 'construct' a entanglement is to use classical information. Or better expressed, measuring on them getting a outcome, is a result of a prearranged construction and order of causality. And that one is still classical even if the opposite 'spins' found are instantaneous.

That’s not what is being done here.

[yor_on]

I see your point Collin. You define this experiment as resting on a classical channel if I read you right. That you will need to foreknow the energy put into the entangled system to be able to extract the same energy at 'B'. If it is that way it leads to the idea of using it as a (FTL) communication meaningless, which I have to admit please me :) Didn't think of that question in form of communication before I read your post.

and no matter what, it is what I originally was wondering about, how one should think of a entanglement. As being 'two particles correlated' or as being 'one indivisible'. Because if you can treat this 'system' in such a way that it allow you to extract more energy than what 'B' initially, before the measurement on 'A', contained then there it is a difference, at least to me.
=

The difference being that although you can't disprove the idea of something getting correlated at its origin, aka a beam through a beam splitter, the later improvement in where energy injected at 'A' while measuring it becomes extractable at 'B' points to it not being so. Unless you want to question causality / time but that will only make it even more complicated.

[yor_on]

But it also makes the idea of a particles 'intrinsic energy' questionable, doesn't it? After all, everything, presuming f.ex light (photons) and atoms to be 'time less' should be entangled at a Big Bang.

[yor_on]

And I'm still not sure how to read that paper?
The wording creates a ambivalence.

As this " Next, the measurement result is announced to another subsystem B of the many-body system at a speed much faster than the diffusion velocity of the energy infused by the measurement."

First of all it defines it as being a 'speed', wherefrom comes that conclusion?
And a diffusion velocity of energy inside one particle?

you can read that as if it is meant to be a transfer FTL, but I don't see how that conclusion comes to be.

[yor_on]

And Collin, do me the favor of presuming that I do know the difference between the speed of light in a vacuum as defined locally versus something above that limit.

[yor_on]

Damn, this is incredibly embarrassing. I already wrote about this at another site a long time ago. And there I had no problem with the classical definition you use although I found some problems with the idea of it 'lifting out energy' of this vacuum. Here's another paper from him where he describes it more in detail, and where he state what you state too, that it involves a classical channel.

http://www.tuhep.phys.tohoku.ac.jp/~hotta/extended-version-qet-review.pdf

I'll blame it on senility being a burden we all will share :)
=

Hmm, I've been away from entanglements for a rather long time. I mean really thinking about it.
Here's a twist.

=========================
"
    If I get it right the idea is that without a sub-channel for each entanglement the 'receiver', inadvertently, might end up as the sender?

    Assume that I have a 'timer' at the receivers end, and ten entanglements. The sender send one sub-message, defining a time rate, which the receiver then set the timer to. The timer then proceed to measure each of the entanglements successively according to the defined time rate. Would that still be a 'indeterministic flow', or is it something more I'm missing here?

    ...

    This is tricky.

Yep, a bit!

If you set up a prearranged timing between A and B, the net "energy" received by B will approach zero in all cases. Hotta's trick is to tell B the proper measurement basis for each individual trial. Because each AB pair is different, of course! A pre-arranged plan gets you nothing, the results are simply random! Instead, A tells B what to expect, and B responds accordingly knowing the now predetermined outcome.

It is important to note that is is NOT true that applying some energy at A causes energy to appear at B. It does not matter how much energy is invested by A, that does not change what occurs at B. That is NOT the mechanism.

Honestly, this is a very complex subject and all I can really tell you is that calling it Energy Teleportation is misleading as a lay term. This is a scientific label, and you should not take it too seriously. "
==============================================

What one might do is to connect it to Jeffreys post about 'Quantum Bayesianism'. https://en.m.wikipedia.org/wiki/Quantum_Bayesianism   versus  ' the many worlds theory ' https://www.thoughtco.com/many-worlds-interpretation-of-quantum-physics-2699358

And why you might want to do this should be depending on how you look at those theories. If you go out from a definition in where your expectations defines the outcome, or at least influence it, then the idea of each arrangement having its own unique identity?

From the position of A, everything will be delivered as arranged once and for all by this first stl (including at 'c':) 'sub-channel' presenting the arrangement, if I'm thinking right here. From the position of 'B' though, measuring as defined by 'A', (assuming causality to exist between them and so a possibility for those to define each others time) it then becomes a test of those ideas. In a many worlds theory you can't define your own as the 'primary' link of a chain of bifurcations, even though we take it for granted as that is what probability state. So presuming probability to hold, there should be a possibility of finding that sequential prearranged ordering of measurements to deliver you energy, as it seems to me. (as a statistical possibility)

In the other case where your expectation influence the experiment, then it comes down to what those expectations are, doesn't it?
 

In other words, it comes down to the statistics of those experiments, done until you get a significant amount of them. That is if I'm thinking right here? All of this presuming the paper to be correct otherwise.

Or, a entanglement is independent of those theories?
=

Actually it becomes even murkier than that if you define it such as with a sub channel working you can lift our 'energy' of a vacuum. Energy conservation ignored, it's still about your intention, isn't it? The sub channel doing one thing, enabling you by it's expressed intention to find energy that otherwise wouldn't be found. I have to admit that I find that paper hard to swallow. And yes, that's also the way I connected it to 'Quantum Bayesianism' versus 'many worlds'.

[Colin2B]

And Collin, do me the favor of presuming that I do know the difference between the speed of light in a vacuum as defined locally versus something above that limit.

I would always do that, but with my TNS education hat on I am always looking at how our interested readers are interpreting what they read here, or might misinterpret.
I agree quantum teleportation is poorly named and had almost said the same thing; quantum photocopying more like.