QDev Seminar: Andrew Doherty

Quantum Chemistry on Quantum Computers

Simulations of quantum systems are one of the key applications that are envisaged for quantum computers. One specific application that has been much studied is to solve problems in quantum chemistry. A standard problem is to estimate the ground state energy of a given molecule. Very small numbers of qubits would be required to perform simulations on molecules that are far beyond the reach of current classical computers. However it has recently been realised that the standard approach to quantum simulations is very expensive in terms of the number of gates that must be performed. 
I will describe our recent work which proposes several new approaches to this problem and improves the analysis of the performance of the various algorithms. In recent months the best estimates of the amount of computation required to solve interesting quantum chemistry problems has fallen by several orders of magnitude, suggesting that quantum simulations of this kind may perhaps be tractable on small quantum computers.