Quantum Entanglement

[Kyle]

Have we talked about this? Read this LA Times story and then get back here:

http://www.latimes.com/science/sciencen ... story.html

So a Chinese team sent up a satellite with a photon splitter, that laser split a photon and precisely sent its two quantum-entangled photon "daughters" to two different locations over 620 miles apart. Now, by observing and manipulating one of those photons in one location, it can instantly (meaning- faster than light can travel) communicate with the other location.

This is a big deal, y'all. I just-- I don't know what to say. This is amazing.

[Mike]

Yes. The difficulties involved in making it work AND making it useful are enormous, but it's what will probably lead to some form of faster-than-light communication system in 50 years.

And the implications for what it means for computing power are totally beyond my understanding.

[Kyle]

[Zen]

I was going to post a link to this a while back and got distracted... thanks for posting it! I found it very interesting that they needed to use an orbital installation to get results because of atmospheric interference or whatever it was... It's really cool...

[Stan]

Reminds me of old SF, like Ursula Leguin, where travel was Einsteinian but communication was instant. If you could permanently magnetically capture these particles on an organized manner, you'd have a communicator that could talk only to its twin. It would be hard to have much bandwith as each particle is only a bit. I've thought about a fictional universe where ships communicate with each other through a central hub that has one of every paired communicator. Then that hub is destroyed.

I could see space exploration proceeding this way, drones without the lag.

[Kyle]

[Kyle]

[Mike]

As I understand it, you can't contain these photons for continued use, and you can't use them in atmosphere, because ANY interference means you can no longer determine anything from quantum entanglement. So instead, you'd need a constant stream of particles that are being split and sent from a single central source through a vacuum. Knowing the starting state of those particles (which I assume we'd predetermine), then detectors at one receiver can interpret changes made at the other receiver. But you'd need a constant stream of particles, AND you'd need a way for particles sent at the same time to be hitting both receivers at exactly the same time... ALL the time. When you're dealing with bodies in space (transmitter plus two different receivers) that are all moving in different directions at different speeds, the challenge of lining all of that up becomes enormous.

I figure we'll find a way around all of that eventually, but Morse code is a good comparison. The first practical iterations of this (if it works) will be essentially emergency beacons with little more than an on/off signal, maybe followed by very basic text info, until eventually we get something that equals FTL fiber lines through space.

My solution in the God's Dice game was to remove that central broadcaster, and assume that if we calibrated correctly, we could beam directly from one station to another. It required incredible amounts of processing power to adjust for movement and gravitational variations in spacetime. Plus, establishing a beam required calibration at light speed (8 hours to send a signal to Saturn, plus 8 more hours to wait for the return signal, but then calibration is complete, and communication is instantaneous as long as you don't lose contact for any reason.)

[Stan]

[Bonefish]

oof. 10-20 year transit time for near stars pretty much means you need to get around 99% of C. And that's...questionable. 10% C seems... vaguely possible with what I think we can pull off the shelf in the next couple decades. And that still means something like 30 year transits to our closest stars.

[bralbovsky]

It's troublingly close to infinite improbability.

[Phoebe]

No doubt we'll see some cool developments from this, but keep in mind it took them over a decade to get this far with this one thing. It will be a lot harder to do it in daytime. On the other hand, they've managed to send the split photons through a short distance of water and maintain the entanglement. I have absolutely no idea what distance starts to become an impressive feat as opposed to an unsurprising one.

I'm more focused on two things this result tells us: one, that we can expect China to control any kind of emergent technologies in these areas because we're not investing in this type of research at the rate they are and we're living in a situation where half the people in the country think that higher education is suspicious and a waste of time for most students in the first place. If you stop and think about that for a minute it is absolutely unbelievable. A nation of mostly-immigrants, along with large populations whose ancestors were forcibly enslaved or forcibly pushed off their native land, such that the vast majority of these people had absolutely no access to education and were at the mercy of whoever controlled the resources, and therefore for whom education was an obvious boon to social mobility and life control that they pursued vigorously whenever they were given the opportunity... the grandchildren and great-grandchildren of these people spend their energies devaluing educational achievement relative to things like football prowess and dance teams, and many think college is a waste of time. How does a bunch of people who have been convinced that scientific reports about changes in climate are all a lie, go on as a society to encourage education and investment in physics? The US is going to be a worse place because of it in a few decades if we don't get our heads on straight.

The second thing is that if quantum entanglement can be manipulated in this way, what about all the ways it is naturally occurring without the manipulation? One of the weirdest sources of weird experiences I've had in life is the ability to have information about people who are related to me that I really shouldn't have been able to have. I assume there is a natural rather than supernatural explanation for this, and this seems like one of the best bets for somehow getting at that. Most things that are written for the popular audience about this are a soup of nonsense. But maybe there's something here and we're just going to have to wait and see what scientists figure out about it.

[Mike]

A while back, SarahBeth shared with us that a group of Canadian scientists did this exact same thing over fiber optic lines.

[Phoebe]

Sure, they're doing this type of research in many places around the world, including the U.S. But Trump plans to slash the funding of one of the primary places that works on it by some crazy figure and I'm not seeing Paul Ryan as the saviour of scientific research, though apparently his intensive study of Rand has made him quite the "brain". The Chinese have accomplished some amazing stuff here.