



01191nas a2200145   4500008004100000245004800041210004800089260001400137490000800151520079000159100001800949700001900967700002200986856003701008       2019                        eng d00aAccelerated Variational Quantum Eigensolver0 aAccelerated Variational Quantum Eigensolver  c3/25/20190 v1223 a<p>The problem of finding the ground state energy of a Hamiltonian using a quantum computer is currently solved using either the quantum phase estimation (QPE) or variational quantum eigensolver (VQE) algorithms. For precision ε, QPE requires O(1) repetitions of circuits with depth O(1/ε), whereas each expectation estimation subroutine within VQE requires O(1/ε2) samples from circuits with depth O(1). We propose a generalised VQE algorithm that interpolates between these two regimes via a free parameter α&isin;[0,1] which can exploit quantum coherence over a circuit depth of O(1/εα) to reduce the number of samples to O(1/ε2(1&minus;α)). Along the way, we give a new routine for expectation estimation under limited quantum resources that is of independent interest.</p>1 aWang, Daochen1 aHiggott, Oscar1 aBrierley, Stephen  uhttps://arxiv.org/abs/1802.00171