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European Researchers Propose Quantum Network Between Earth and ISS
New kalalau_kane writes with this tidbit from Extreme Tech: "A group of European researchers has proposed the largest quantum network yet: Between Earth and the International Space Station. Such a network would see entangled photons transmitted over a distance of 250 miles — two or three times greater than previous quantum communication experiments. Not only will this be the first quantum experiment in space, but it will allow the scientists to see if entanglement really is instantaneous over long distances, and whether it's affected by gravity."
The proposal (licensed CC BY).
And Miss Piggy?
From the article: "As we recently reported, another research group recently showed this quantum channel to be at least 10,000 times faster than the speed of light."
I don't get it. I thought it was instantaneous and that number is just a crap number based on distance.
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While the ISS may be only 250 miles above the ground, I can't imagine they only intend to do tests when the ISS is directly above the transmitter. I suspect the journalist completely failed at understanding the spatial relationship between a space station and a spot on the ground.
Quantum entanglement is one of those more sci-fi than actual science, and yet it's a real thing we can't quite explain yet. Testing whether it's affected by gravity is a very cool method of poking the phenomenon a bit more. Maybe one day we'll get an answer besides "It's a quantum thing! You wouldn't understand!"
Occasionally living proof of the Ballmer peak.
Can someone please explain to me why this can't be used for instantaneous communication purposes? From everything I've understood so far, the answer is still no, it can't be used to transmit information, just measure state of the particle at a particular point in time.
Wow - a dozen or so messages and not yet one from quantum-entanglement (QE) deniers.
Presumably, the ability to shoot a beam of light >250 miles, without needing to build a 250-mile-long evacuated beamline, is a major advantage gained. The Earth is surrounded by this annoying thing called "the atmosphere," which wreaks havoc with light traveling only a few miles; the faster you can get out of the atmosphere (by, e.g., shooting straight up), the easier it'll be to get any useful amount of light to the other end.
Very few scientific advances have been made without a few Unforeseen Consequences, but that's no reason for Apprehension or Questionable Ethics so we may just need to Forget About Freeman.
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No, the article isn't suggesting this, but every time quantum entanglement gets brought up on Slashdot, someone suggests how we can use it to communicate FTL. Quantum entanglement is the equivalent of instantaneously sending a random message (more complicate than that, really). No information is actually transmitted. The first time I tried to wrap my head around Quantum Entanglement, I thought it could be used to communicate to far-away places (even other planets) with no latency, but as I understood more, my hopes were dashed.
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This is bullshit. The scientific content behind this claim is that "nonlocal realistic models that reproduce the results of quantum mechanics must have speed of communication at least 10,000 faster than the speed of light in some arbitrary ference frame that we've chosen".
This means that this number is completely irrelevant, i.e., does not measure anyhting related to the real world.
What can be said, scientifically, about the speed of this channel is that it is the speed of light, because we can only actually measure the presence of the information on the other side after a light signal is sent from one party to the other.
The fact that it looks instantaneous is more of an artifact of our mathematical formalism, and a common philosophical misunderstanding about the nature of the quantum state (i.e., people regard it as objective rather than subjective).
entropy happens
Not quite true. The equations appear to be complete - i.e. they appear accurate to within the limits of current experimental error; however, assuming we're not living in The Matrix, the equations are only a mathematical model of a physical reality that we still have very little understanding of, hence the various superstring, etc. theories that seek to explain the equations. Prediction is only half of what science strives for, and the understanding still eludes us.
Moreover, there are theoretical inconsistencies between QM and Relativity, which implies that one or both mathematical models are still incomplete. Glossing over that fact is likely to prove quite similar to the preeminent experts in the late 1800's who stated that everything in science was known except for a few minor unexplained phenomena such as black-body radiation, etc. Investigating those inconsistencies eventually exposed almost every established theory in physics as fundamentally incomplete, and in the absence of evidence to the contrary that seems to be the safe bet for the current situation as well. After all, rigorous science is only a few centuries old, and every major advance to date has revealed far more questions than answers.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
Depending on the experiment, 10% differences can be pretty obvious to measure. With the best atomic clocks, we can now see relativistic effects due to gravitational potential differences corresponding to 1m height change in the lab. Without understanding the experiment, you have no way to judge whether 10% differences are negligible or whoppingly huge compared to experimental sensitivity.
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When the hell are we going to get HL3?? I don't even ask for that much, a new HL2 episode would be nice!
(pardon moi a bit of internet rage just in case some valve guy is actually reading this)
What the article fails to point out is that actually nothing is travelling faster than light. This is the fancy equivalent of shining a bright laser on the moon and moving it around so that it appears that the bright spot on the surface moves at a velocity in excess of c. There is no problem with this because no information is transmitted from one point on the moon to another point on the moon faster than c - the only information which is transmitted is from the person pointing the laser to the moon. In the same way no data is transmitted between the two people making the measurements because neither has any control over the outcome of their measurement.
1. Put a really long stick so that the ends reach the two points you want to communicate.
2. Push the stick from one end and it moves at the same time on the other end for instantaneous FTL communication.
3. Sell sticks to day traders.
4. Profit.
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No. We KNOW they are incomplete because they cannot be reconciled with relativity which we have also tested. That means that there is necessarily something missing.