Accelerated Variational Quantum Eigensolver

Apr 12, 2019
5 pages
Published in:
  • Phys.Rev.Lett. 122 (2019) 14, 140504
  • Published: Apr 12, 2019

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Abstract: (APS)
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 generalized 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.Received 18 June 2018Revised 18 December 2018DOI:https://doi.org/10.1103/PhysRevLett.122.140504© 2019 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasQuantum algorithmsQuantum simulationQuantum Information, Science & Technology
  • Quantum Information, Science & Technology
  • Quantum algorithms
  • Quantum simulation