NASA's Plan To Turn the ISS Into a Quantum Laser Lab (wired.com) 20
Daniel Oberhaus writes via Wired: Later this summer, physicists at the Argonne and Fermi national laboratories will exchange quantum information across 30 miles of optical fiber running beneath the suburbs of Chicago. One lab will generate a pair of entangled photons -- particles that have identical states and are linked in such a way that what happens to one happens to the other -- and send them to their colleagues at the other lab, who will extract the quantum information carried by these particles of light. By establishing this two-way link, the labs will become the first nodes in what the researchers hope will one day be a quantum internet linking quantum computers around the nation. [...] The problem is that quantum information hates long-distance travel. Send entangled photons out into the real world through optical fiber and, in less than 50 miles, environmental interference will destroy their quantum state. But if the photons were relayed through a satellite instead, they could be sent to destinations hundreds -- and potentially thousands -- of miles away. So in 2018, NASA partnered with MIT's Lincoln Laboratory to develop the technologies needed to make it happen.
The goal of the National Space Quantum Laboratory program, sometimes referred to as Quantum Technology in Space, is to use a laser system on the International Space Station to exchange quantum information between two devices on Earth without a physical link. The refrigerator-sized module would be attached to the outside of the space station and would generate the entangled photons that carry the quantum information to Earth. The demonstration would pave the way for a satellite that could take entangled particles generated in local quantum networks and send them to far-flung locations.
The goal of the National Space Quantum Laboratory program, sometimes referred to as Quantum Technology in Space, is to use a laser system on the International Space Station to exchange quantum information between two devices on Earth without a physical link. The refrigerator-sized module would be attached to the outside of the space station and would generate the entangled photons that carry the quantum information to Earth. The demonstration would pave the way for a satellite that could take entangled particles generated in local quantum networks and send them to far-flung locations.
Schrödinger (Score:4, Funny)
While they are at it maybe they could test out Schrödinger's theory using the two coronavirus cats.
Lasers from space (Score:1)
We're doomed!!!1
Didn't realize until today (Score:2)
there were quantum lasers and other, non-quantum lasers.
But then, on slashdot it is live and learn...
Re: (Score:2)
I'm not alone (Score:3)
"The problem is that quantum information hates long-distance travel. "
Me too.
What's the point? (Score:3)
Entanglement is the source of many of the advantages of a quantum network, since it allows for information to be exchanged between two particles no matter how far apart they happen to be
But not classical information - quantum information. This also requires an auxiliary classical transmission protocol. With those requirements, what's the gain of a quantum network? I cannot imagine a use-case.
You hear about quantum security, but the no-teleportation theorem [wikipedia.org] states that you cannot arbitrarily create quantum information from classical information or vice versa, so it's all stuck in a black box; infinite security, but no purpose.
Re:What's the point? (Score:4, Interesting)
Re: (Score:2)
Entanglement is the source of many of the advantages of a quantum network, since it allows for information to be exchanged between two particles no matter how far apart they happen to be
But not classical information - quantum information. This also requires an auxiliary classical transmission protocol. With those requirements, what's the gain of a quantum network? I cannot imagine a use-case.
You hear about quantum security, but the no-teleportation theorem [wikipedia.org] states that you cannot arbitrarily create quantum information from classical information or vice versa, so it's all stuck in a black box; infinite security, but no purpose.
The no-teleportation theorem doesn't mean quantum information is "stuck in a black box". It just means you can't replicate a quantum state with classical information.
Basically, in the wave-function representation a quantum state has two components, the real and imaginary parts; but a measurement will give you only one of the components (observations are Hermitian operators). So you will always lose one component of the quantum state when you make a measurement (and the measurement destroys the state, so yo
Re: What's the point? (Score:5, Informative)
Entanglement (Score:1)
Re:Entanglement (Score:4, Informative)
Isn't sending both of them counterproductive and isn't the act of sending entangled photons defeating the purpose of the entanglement?
No, you sent one member of the pair to one receiver, and the other member of the pair to the other, so the two receivers now each have one member of the entangled pair. It means that the two receivers don't have to have all the technology to be able to generate entangled photons, they only need to be able to measure polarization.
They should be keeping one and sending one, why the hell would you send both?
If somebody were trying to relay a quantum entangled photon from a sender on the Earth via the space station to the receiver, the space station would have to receive the quantum entangled photon and then relay it to the receiver without destroying it. This may be possible in theory, but it is really really hard to receive and retransmit a photon without destroying its quantum state. (Obviously that could be done by a mirror, but if the relay were merely a mirror in space the signal intensity would be so low as to be indetectable).
Shouldn't they entangle both photons at separate locations to begin with to prevent having to send them anywhere? I'm guessing it is not possible to entangle two particles that are already separated by some distance or this would be the preferred route?
Would be nice, but we don't know how to entangle two particles at different locations other than by generating an entangled pair somewhere and sending one member of the pair to each location.
Re: Entanglement (Score:1)
Re: (Score:2)
Wow thank you for all that excellent information! I didn't realize they were trying to generate these for sending to two receivers. Might be easier to start with sending one particle to a receiver and using the ISS as the other receiver temporarily until entangled photon transport is worked out properly.
True, but sending signals from earth to space via quantum entanglement has already been done.
I have a couple more questions, please? How does one entangle a photon and other particles?
Easiest way to create a pair of entangled photons is to take a single photon and split it into two photons of half the energy, using a wavelength doubler ("parametric downconversion"). But you can also create a pair by pumping a system that decays by emiting two photons.
Is it possible to entangle an atom of any element, say for instance, antimony so that it could work with the nuclear electric resonance nano device that was posted on slashdot a few weeks ago?
In principle you could entangle an atom of pretty much a
Point to point - why not? (Score:2)
Last published reports entanglement communication traversed miles successfully. Radio frequency waves respect distance line of sight communication. Upping the line of sight from terrestrial measure to vacuum of space should be one interesting experiment.
curious how this works? (Score:2)
How does this work? Is it that they create a pair, then send JUST ONE to the destination, then manually twiddle one, then at the other location, the other one self-twiddles due to entanglement, and they read how it twiddled?
NASA could neither confirm nor deny... (Score:2)
Re: NASA could neither confirm nor deny... (Score:1)