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You need an exponential increase in performance (power of N) to simulate an increasing number of molecules, while for quantum computers you may need only a poly
by mtgx 9y ago
You need an exponential increase in performance (power of N) to simulate an increasing number of molecules, while for quantum computers you may need only a polynomial increase in performance (power of 2).
So it's possible to simulate 25-qubit-level chemistry with a laptop, 50-qubit-level chemistry with a supercomputer, and 100-qubit-level simulation with a supercomputer is impossible and will be impossible for a very long time.
But going from a 50-qubit quantum computer to a 100-qubit one may take just 2 years (or 4, it doesn't really matter), and then another 2 years to get to 200 qubits, and so on. Quantum computers will solve chemistry problems in minutes that would otherwise have taken 100 years to simulate.
- jabl 9y agoSo what I'm asking is how does a quantum computer solve quantum chemistry problems? To make it concrete, say I want to calculate the band structure of a crystal using a quantum computer? What do I do? What kind of algorithms can the QC run that solves this problem faster/better than, say, a DFT code? I don't think it's a given that just because I want to simulate a quantum mechanical system in some way, that a quantum computer is a useful tool. Or it might be, I don't know. I just don't think it's enough justification that there happens to be the word "quantum" in both the problem description and in the name of the computer.