Everything John Preskill said on any show that made the record, most notable first. Each card names its show and opens the statement there.
Preskill: Grover's algorithm only doubles tractable cities in traveling salesman problems
“And in practice, it's not that big a deal. What it means is that, you know, if you have the same processing speed, you can handle about you know, twice as many cities before the problem becomes too hard to solve as you could if you were using a classical proce…”
Preskill: Current quantum computers are too small for proposed algorithms
“We have algorithms that have been proposed, but, which we can't really run currently, because our quantum computers aren't big enough, on the scale that's needed to solve problems really, people really care about.”
Preskill: Current quantum tech achieves gate error rates around a few parts per thousand
“More or less with the technology we have now, you can have a gate error rate of a few parts in a thousand, you know.”
Preskill: Superconducting qubit coherence times grew 10x every three years
“And for the superconducting circuits, those coherence times have increased about a factor of 10 every three years, going back 15 years or so.”
Preskill: Superconducting circuits execute gates faster than trapped-ion qubits
“They have the advantage of being faster than the time to take the cycle time, the time to do a gate is faster than with the trapped ions.”
Preskill: Quantum computers can break both RSA and elliptic curve cryptography
“RSA, which is one of the ones that's widely used, as typically practiced today, the, to break it, you'd have to do something like factor a number, which is Over 2000 bits long to 20 48. And that's, you know, that's too hard to do now. But that's what quantum c…”
Preskill: Quantum information can travel tens of kilometers in fiber with low error
“But nowadays, you know, you can send quantum information through an optical fiber over tens of kilometers with you know, a low enough error rate, so it's useful for communication.”
Preskill: Quantum repeaters require much smaller processors than computing hard problems
“And so it will require some quantum processing to get that quantum error correction in the quantum repeater to work. But it's a much more modest scale quantum processor than we would need to solve hard problems.”
Preskill: Quantum entanglement does not enable faster-than-light communication
“What sometimes Gets said, or the impression people get, is that that means that when I do something to my qubit, it instantaneously affects your qubit, even if we're on different sides of the galaxy. But that's not what entanglement does. It just means they're…”
Preskill: Single photons cannot reach global distances in fiber without repeaters
“Because at least with, you know, our current photonics technology, there's no way I can send a single photon from here to China without there being a very high probability that it gets lost in the fiber somewhere.”
Preskill: Many classical computer algorithms were discovered empirically through experimentation
“A lot of classical algorithms that, that people use on today's computers were discovered, or that they were powerful, was discovered by experimenting, you know, by trying it.”
John Preskill
the Y Combinator Startup Podcast 1