Tuesday, January 13, 2015

Supposed advance in quantum computing

MIt computer scientist Scott Aaronson has finished defending himself against weirdo feminist attacks on his personal life, and is back to promoting quantum computing:
Within the last couple months, there was a major milestone in the quest to build a scalable quantum computer, and also a major milestone in the quest to figure out what you would do with a quantum computer if you had one. As I’ve admitted many times, neither of those two quests is really the reason why I got into quantum computing — I’m one of the people who would still want to study this field, even if there were no serious prospect either of building a quantum computer or of doing anything useful with it for a thousand years — but for some reason that I don’t fully understand, both of those goals do seem to excite other people.
I am pretty sure he is being sarcastic here. Yes, of course interest in quantum computing is based on the hope that such computers can be built and do useful things. He sounds like G.H. Hardy showing contempt for math doing anything useful.

Scott sure gets excited if someone like D-Wave claims that a quantum computer has been built, or someone like me claims that it is impossible.

I am wondering what these guys think about the possibility that we live in a computer simulation. Since I don't believe that scalable super-Turing quantum computing is possible, the simulator would be a classical computer. So if these quantum computing experiments are successful, then they would put an incredible computational strain on the simulator. What if they overload the simulator? We would all effectively die. This is a bigger threat to the world than the possibility of the LHC making a black hole that swallows the Earth.

Update: A comment says:
If the simulating computer of our world is resource scarce, what if we try to construct a quantum computer to apply Shor's algorithm? Do it for discrete logs or elliptic curve logs because they are uniformly hard. To pick a "hard" integer to factorize as a test, we pretty much have to come up with two large prime numbers first, and our simulator can just read off the prime numbers during generation, and then feed them into the output of the simulated quantum computer. But if we pick a random instance of a discrete log or an elliptic curve log, either Shor's algorithm would myseriously break down, or our simulator is at least partially a quantum computer on its own.
The answer is that it would deplete the resources of the simulator, and give us a cosmic blue screen of death. You have been warned.

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