| Pretty lost yeah, but you're asking questions which is better than 90% of the people who are lost. Some very brief answers: They're called qubits; a cubit is a length about 50cm. Pronounced the same though. Quantum computers are not about being able to change connections in real time. We know how powerful such a computer could be (it can be simulated by a classical computer in polynomial time), and quantum computers are more powerful than that. (Some nitpicker is going to swoop by and say that technically we haven't proven that BQP != P, but if BQP==P then quantum computers are useless anyways.) Quantum amplitudes are not just probabilities: they can be imaginary, and they can be negative. You can add up two non-zero amplitudes and get 0, which is very much not how probabilities work. You can't have a non-zero probability that A happens and a non-zero probability that B happens but a zero probability that A OR B happens, yet with quantum mechanics you get exactly that. Whatever intuition you have for how quantum computers works, it's wrong. Plenty of people have considered that the brain is doing quantum computations. It seems unlikely because the brain is large, wet, and hot, and quantum mechanical systems really like to decohere under those circumstances (breaking the computation). But Roger Penrose still thinks they are. The main takeaway I'd like to convey is that quantum computers are vastly better than classical computers for a few very specialized tasks like taking discrete logarithms and factoring, and no better than classical computers for most everything else. (Vastly better meaning exponentially better: it takes a classical computer with roughly 2^1000 bits of memory to simulate a quantum computer with 1000 bits of memory.) |