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Single Photons Bounced Off Orbiting Satellite
KentuckyFC writes "If we're ever going to benefit from the perfect security of quantum communication, we're going to need ways of transmitting entangled photons around the globe and certainly further than the current record of 144km through the atmosphere. Anton Zeilinger at the University of Vienna and colleagues have taken an important step towards this by bouncing individual photons off the Ajisai geodetic satellite (essentially a space-based disco ball) which is orbiting at 1400km. The group says the experiment is an important proof of principle for satellite-based quantum communications."
Not to mention photons are like words: you shouldn't use those you don't understand. Is it a wave or is it matter? Huh, Mr. Smarty Pants? Oh, what's that you say? A boson followed by a long explanation, how utterly predictable! Ha, you would say that. No. I want answers and I wanted them back when the church would persecute you for publishing them!
We need something smaller. Go back to the lab, anything larger than a Planck Length is unacceptable. And only 1400km? So help me god, if you can't express the distance it travels in double up arrow notation or tetration, I don't want to hear about it. Come on people, this is real science, not some religious mumbo jumbo (6,000 years? Is that the absolute limit of your imagination!?)
My work here is dung.
This is just an elaborate game of pong, isn't it...
I record my sleeptalking
From my understanding it does serve a practical purpose in that intercepting the message changes it. Thus while you can't stop people from tapping into your message, you do have instant feedback about when that happens.
I am Slashdot. Are you Slashdot as well?
Breaking quantum cryptography is not hard, it is impossible. The security is guaranteed by the laws of physics. Unless quantum mechanics is flat out wrong, it can never be broken, period. And saying quantum mechanics could be wrong is like saying gravity could be wrong.
About quantum computing, it's actually closer to providing new computational powers than you might think. In terms of a powerful, programmable computer that can factor large numbers, we are a long way off. But in terms of being able to simulate certain quantum systems that current supercomputers cannot, we are fairly close.
Ah, ha, ha. ha, staying entangled, staying entangled
Ah, ha, ha, ha, staying entaaa-aaaan-gleeee-eeeed, oh yeah!
Well, you can tell by the way that I've been spun,
I'm either a zero, or eyther a one.
Quantum entangled far and long.
I've been a qubit since I was born.
And now it's all right, it's O.K.
But you must look the other way.
'Cos if you look, you'll understand
A quantum state's effect on man.
Whether you're a top or whether you're a bottom
You're quantumly entangled, quantumly entangled
Though we're separated, our states are identicated
We're staying entangled, staying entangled
Ah, ha, ha, ha, staying entangled, staying entangled
Ah, ha, ha, ha, staying entaaa-aaaan-gleeee-eeeed, oh yeah!
Light goin' nowhere
Quanta probability
Someone observe me now
Light goin' nowhere
Someone observe me now
I'm stayin' entangled
Oh, say does that Star-Spangled Banner entwine / The myrtle of Venus with Bacchus's vine?
Others have created quantum crypto systems that take the possibility of cloning into account, http://w3.antd.nist.gov/pubs/Mink-SPIE-One-Time-Pad-6244_22.pdf
'basic' quantum cryptography that is taught can be hacked This is true but I think not for the reasons you believe. Basic quantum crypto provides confidentiality only. To keep from being hacked, you must provide authentication as well (Alice must be able to prove she is communicating with Bob and not Eve). I haven't heard of a way to do this without falling back onto more conventional cryptographic techniques such as RSA signatures - at least when doing quantum crypto over fiber. Maybe sending photons through the atmosphere means you can actually just see if somebody is acting as a man-in-the-middle.