TY - JOUR T1 - Accelerated Variational Quantum Eigensolver JF - Phys. Rev. Lett. Y1 - 2019 A1 - Daochen Wang A1 - Oscar Higgott A1 - Stephen Brierley AB -

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∈[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−α)). Along the way, we give a new routine for expectation estimation under limited quantum resources that is of independent interest.

VL - 122 UR - https://arxiv.org/abs/1802.00171 CP - 140504 U5 - https://doi.org/10.1103/PhysRevLett.122.140504 ER -