This is a transparent attempt to develop a military communication system that bipassses US suvalience.
Chinese satellite is one giant step for the quantum internet
21–29 of 29 posts
Re: Chinese satellite is one giant step for the quantum internet
#22> Eventually, quantum teleportation in space could even allow researchers to combine photons from satellites to make a distributed telescope with an effective aperture the size of Earth — and enormous resolution. “You could not just see planets,” says Kwiat, “but in principle read licence plates on Jupiter’s moons.” Uh, what? What does entangled photons have to do with interferometry-based astronomy? Can somebody exp…
I believe they're referring to this proposal by Gottesman [0]. I will try to explain in layman's terms what is happening: the simplest telescope array you can imagine is just two telescopes separated by what is called the baseline. The telescopes could either just detect light from a star independently and then autocorrelate these signals afterwards, or they could interfere their signals before detection. The latter is called an interferometric telescope array and has a resolution advantage over the former, simpler, solution. The length of the baseline is an important factor in determining the size of the objects you can resolve with such a telescope, and the goal is generally to make it as large as possible. Unfortunately, as the baseline becomes larger the signals from the two telescopes are likely to become distorted or lost before you can interfere them due to the distance you have to send one to reach the other. The Gottesman paper offers one solution to this, which is to use a quantum repeater (essentially quantum teleportation) to send one of the telescope's signals to the other telescope without any loss or degradation, in principle allowing for arbitrarily long baselines in telescopes.
Re: Chinese satellite is one giant step for the quantum internet
#23This is a pretty interesting article! I have some questions, though:
1. What properties of space facilitate quantum experiments more than terrestrial environments? Reduced gravity? Vacuums?
2. How does the satellite create pairs of entangled photons? I missed the memo that we could control entanglement...
3. When two photons are entangled, what kinds of properties about them are useful to observe/control, that give us information about or control of the twin? All I can think of are positional properties like position, speed, acceleration, etc...
Re: Chinese satellite is one giant step for the quantum internet
#24> Eventually, quantum teleportation in space could even allow researchers to combine photons from satellites to make a distributed telescope with an effective aperture the size of Earth — and enormous resolution. “You could not just see planets,” says Kwiat, “but in principle read licence plates on Jupiter’s moons.” Uh, what? What does entangled photons have to do with interferometry-based astronomy? Can somebody exp…
It lets you bypass some classical limits. It's a well known idea. For example, John Preskill mentioned entangled telescopes in a non-technical talk back in February [1]. A specific case is "NOON" states [2]: > NOON states are an important concept in quantum metrology and quantum sensing for their ability to make precision phase measurements when used in an optical interferometer. --- Here's an example that doesn't ex…
Thanks, I actually understood that!
Re: Chinese satellite is one giant step for the quantum internet
#25> Eventually, quantum teleportation in space could even allow researchers to combine photons from satellites to make a distributed telescope with an effective aperture the size of Earth — and enormous resolution. “You could not just see planets,” says Kwiat, “but in principle read licence plates on Jupiter’s moons.” Uh, what? What does entangled photons have to do with interferometry-based astronomy? Can somebody exp…
I can already read all of the license plate data on Jupiter's moons. The log is attached below:
Well, it is theoretically possible that life exists deep inside Jupiter. They may even have cars and license plates.
But then again, even a quantum telescope might not be able to see it either.
Re: Chinese satellite is one giant step for the quantum internet
#26This is a pretty interesting article! I have some questions, though: 1. What properties of space facilitate quantum experiments more than terrestrial environments? Reduced gravity? Vacuums? 2. How does the satellite create pairs of entangled photons? I missed the memo that we could control entanglement... 3. When two photons are entangled, what kinds of properties about them are useful to observe/control, that give u…
The quantum computers on earth work by cooling the processors to sub-zero (close to zero Calvin) temperatures. And space is dead cold. So that may be a factor. Also, the article mentions that light travels uninhibited in space.
Re: Chinese satellite is one giant step for the quantum internet
#27This is a pretty interesting article! I have some questions, though: 1. What properties of space facilitate quantum experiments more than terrestrial environments? Reduced gravity? Vacuums? 2. How does the satellite create pairs of entangled photons? I missed the memo that we could control entanglement... 3. When two photons are entangled, what kinds of properties about them are useful to observe/control, that give u…
1. Yeah space so nothing disturbs the photons
2. "heart of their satellite is a crystal that produces pairs of entangled photons" (see https://en.wikipedia.org/wiki/Spontaneous_parametric_down-co...)
3. Mostly polarization
Re: Chinese satellite is one giant step for the quantum internet
#28Could these satellites have any implications for Facebook's drone and Google's Loon internet connectivity projects?
Re: Chinese satellite is one giant step for the quantum internet
#29deploy GFW is the next step