Abstract
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 , QPE requires repetitions of circuits with depth , whereas each expectation estimation subroutine within VQE requires samples from circuits with depth . We propose a generalized VQE algorithm that interpolates between these two regimes via a free parameter , which can exploit quantum coherence over a circuit depth of to reduce the number of samples to . Along the way, we give a new routine for expectation estimation under limited quantum resources that is of independent interest.
- Received 18 June 2018
- Revised 18 December 2018
DOI:https://doi.org/10.1103/PhysRevLett.122.140504
© 2019 American Physical Society