Scientists Achieve Direct Counterfactual Quantum Communication
sciencealert.com
sciencealert.com
> Direct counterfactual quantum communication on the other hands relies on something other than quantum entanglement. Instead, it uses a phenomenon called the quantum Zeno effect.
Does it violate the speed of light? No.
> It works based on the fact that, in the quantum world, all light particles can be fully described by wave functions, rather than as particles. So by embedding messages in light the researchers were able to transmit this message without ever directly sending a particle.
Is this a sleight of hand? I don't know... ("New system of angular motion doesn't require radians! Uses 'degrees' instead.")
> ...all light particles can be fully described by wave functions, rather than as particles...
> Intuition from our everyday lives gives rise to the belief that information exchanged between remote parties is carried by physical particles. Surprisingly, in a recent theoretical study .. quantum mechanics was found to allow for communication, even without the actual transmission of physical particles.
ok, does this also mean that communication is free from restraints that particles suffer.. as in would this allow faster than light communication?
Check out the PBS Space Time channel. They have a number of excellent episodes on the speed of light, causality, etc...
what i am interested in is:
i understand that solely utilising quantum entanglement, a ftl phenomenon, one is unable to communicate classical information but does this method utilise the zeno effect to afford this communication by controlling when to cease and reinstate the systems evolution?
two parties with entangled particles within quantum systems agree on a baud rate and the transmitter alters the systems evolution until it takes on a desirable state then arrest the evolution until the next scheduled modulation, then evolve the state to the next desired expression, wait for the next modulation, and on and on
effectively the information transfer would adhere to causality, the observer would be subject to the baud rate, but the distance traveled between the parties could be greater than one that light could travel within that baud rate
Am I missing something?
It's been way to long since my one quantum physics class, but looking at the pretty pictures I think they got their photon to interfere destructively with itself over the entire length of the transmission channel between a pair of beam splitters.
Which I don't think is possible with ordinary waves (say in water), which I suppose is probably what the big deal is.
It means you can stop playing "Where's the photon?" and accept that these experiments are doing spatially distributed probabilistic computing.
In this view there is no photon - there's only a map of possible photon-like event positions distributed in spacetime, and one or more end-points tuned to pick up photon-like events by sampling the map at specific spacetime locations.
The weird part is the way that interactions between the map distributions and the end-points are completely unintuitive, and you can do neat tricks like constraining probabilities by repeatedly connecting to an end-point, and creating dead areas where the probability of an event is zero but which don't "block" events around them.
That just emphasises that the Newtonian-ish view is the wrong model. The right view is still TBD, but it seems to be some kind of holistic summary view that somehow - no one can even begin to guess how - creates a map by integrating over all possible interactions.
This is not what we're used to, but discovering that reality doesn't do what we expect is the point of science, so that's not a bad thing.
http://www.pnas.org/content/114/19/4920.abstract
The image transmitted was a monochrome bitmap graphic of a Chinese knot:
https://upload.wikimedia.org/wikipedia/commons/thumb/f/fb/Ei...
...no resolution noted in the abstract, but probably small and pixelated, since it was serialized as photomultiplier clicks.
Article: "The results will now need to be verified by external researchers to make sure what the researchers saw was a true example of counterfactual quantum communication."
Okay then
This result was published in a peer review journal. It means that two or three experts read the article and found no evident flaw and think that it has enough details to make the experiment in another laboratory [2]. They didn't go to the laboratory and unbolted every piece to double check the setup, or make a copy in their own laboratory to check the experiment. So until two or three more laboratories try this and a few variations, this is still doubtful, but there is a good chance that this is true.
[2] Usually the papers don't have enough information. You have to guess and email the authors and cross your fingers to reproduce the result.
[1] My guess is that they explained this because the result is very unintuitive.