Quantum communication

[Sparko]

China Shatters “Spooky Action at a Distance” Record, Preps for Quantum Internet

Results from the Micius satellite test quantum entanglement, pointing the way toward hack-proof global communications—and a new space race

In a landmark study, a team of Chinese scientists using an experimental satellite has tested quantum entanglement over unprecedented distances, beaming entangled pairs of photons to three ground stations across China—each separated by more than 1,200 kilometers. The test verifies a mysterious and long-held tenet of quantum theory, and firmly establishes China as the front-runner in a burgeoning “quantum space race” to create a secure, quantum-based global communications network—that is, a potentially unhackable “quantum internet” that would be of immense geopolitical importance.

https://www.scientificamerican.com/a...ntum-internet/
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Chinese physicists measure speed of Einstein’s ‘spooky action at a distance’: At least 10,000 times faster than light

A team of Chinese physicists have clocked the speed of spooky action at a distance — the seemingly instantaneous interaction between entangled quantum particles — at more than four orders of magnitude faster than light. Their equipment and methodology doesn’t allow for an exact speed, but four orders of magnitude puts the figure at around 3 trillion meters per second.

https://www.extremetech.com/extreme/...ter-than-light

[seer]

China Shatters “Spooky Action at a Distance” Record, Preps for Quantum Internet

Results from the Micius satellite test quantum entanglement, pointing the way toward hack-proof global communications—and a new space race

In a landmark study, a team of Chinese scientists using an experimental satellite has tested quantum entanglement over unprecedented distances, beaming entangled pairs of photons to three ground stations across China—each separated by more than 1,200 kilometers. The test verifies a mysterious and long-held tenet of quantum theory, and firmly establishes China as the front-runner in a burgeoning “quantum space race” to create a secure, quantum-based global communications network—that is, a potentially unhackable “quantum internet” that would be of immense geopolitical importance.

https://www.scientificamerican.com/a...ntum-internet/
--------------------

Chinese physicists measure speed of Einstein’s ‘spooky action at a distance’: At least 10,000 times faster than light

A team of Chinese physicists have clocked the speed of spooky action at a distance — the seemingly instantaneous interaction between entangled quantum particles — at more than four orders of magnitude faster than light. Their equipment and methodology doesn’t allow for an exact speed, but four orders of magnitude puts the figure at around 3 trillion meters per second.

https://www.extremetech.com/extreme/...ter-than-light

This stuff just does not make sense to me - how does one particle effect another particle at a distance - where is the physical connection?

[Sparko]

This stuff just does not make sense to me - how does one particle effect another particle at a distance - where is the physical connection?

I think basically they become the same particle just at two different locations. So when you mess with one, the other one is instantly affected since it is the same particle in a different space.

[JimL]

I think basically they become the same particle just at two different locations. So when you mess with one, the other one is instantly affected since it is the same particle in a different space.

But 3 trillion meters per second isn't exactly instantaneous, there is a time interval between the communication of one particle to the other, so how could they be the same particle?

[Sparko]

But 3 trillion meters per second isn't exactly instantaneous, there is a time interval between the communication of one particle to the other, so how could they be the same particle?

That was as fast as the instrumentation could measure. It is at LEAST that fast. I don't think they actually ARE the same particle, but somehow they are at a quantum level. They can be disentangled later and then you have two different particles in two different places.

They start out as one particle that is split into two (photons usually) so you have two copies of the original photon which are both exact copies of each other. separate them and they remain the same, change one and you change the other.

[JimL]

I see, Possibly instantaneously! Interesting. And the configuration of the one is dependent upon the observation of the other. No, actually I think the configuration of both is dependent on ones observation of either. I believe thats the copenhagen interpretation. Hmmm, got to go read up on that again, see if I can get even more confused.

[seer]

I think basically they become the same particle just at two different locations. So when you mess with one, the other one is instantly affected since it is the same particle in a different space.

Right that helped! Not - how does one particle exist in two different places?

[seer]

see if I can get even more confused.

exactly, this stuff is strange...

[JimL]

Right that helped! Not - how does one particle exist in two different places?

Not sure if they are exactly the same particle, after all, the one does split off from the other. Maybe being that they are exact copies, they just have the exact same characteristics and so are always in identical positions no matter where they are physically.

[Sparko]

Right that helped! Not - how does one particle exist in two different places?

what you should be asking is how a particle can exist in all states until someone observes it. It is almost like things only exist when you look at them. Which you would expect if you were in a computer simulation. Why waste processor power on rendering things unless someone is paying attention to that particular bit? What if nothing is actually there till you look?

[seer]

what you should be asking is how a particle can exist in all states until someone observes it. It is almost like things only exist when you look at them. Which you would expect if you were in a computer simulation. Why waste processor power on rendering things unless someone is paying attention to that particular bit? What if nothing is actually there till you look?

Then we are back to Berkeley's idealism - funny to think that modern science may prove Berkeley right!

In the Principles and the Three Dialogues Berkeley defends two metaphysical theses: idealism (the claim that everything that exists either is a mind or depends on a mind for its existence) and immaterialism (the claim that matter does not exist). His contention that all physical objects are composed of ideas is encapsulated in his motto esse is percipi (to be is to be perceived).

[seer]

Not sure if they are exactly the same particle, after all, the one does split off from the other. Maybe being that they are exact copies, they just have the exact same characteristics and so are always in identical positions no matter where they are physically.

No that would not be exactly correct - I believe if you change the spin on particle A then the spin on particle B changes. So when we interfere with the natural spin of A that changes the natural spin of B.

[seer]

I wish someone here who knows this stuff would chime in!

[Sparko]

I wish someone here who knows this stuff would chime in!

Don't worry. I am sure Shuny will show up soon with his google results.

[seer]

Don't worry. I am sure Shuny will show up soon with his google results.

Please, please don't let him play!