Contextual Subspace Variational Quantum Eigensolver

ORAL

Abstract

We describe the contextual subspace variational quantum eigensolver (CS-VQE), an approximation method based on the standard variational quantum eigensolver (VQE). CS-VQE obtains a classical approximation to the ground state energy by solving a hidden variables model for a noncontextual approximation to the Hamiltonian. This approximation is then used to construct a smaller VQE instance that computes quantum corrections to this classical approximation in a contextual subspace. CS-VQE is an example of a genuinely hybrid NISQ algorithm in the sense that part of the answer is computed on the classical computer and part of the answer on the quantum computer.

*We acknowledge support from the UK Engineering and Physical Sciences Research Council grants EP/L015242/1 and EP/S021582/1, and from European Commission for VECMA (800925) and EPSRC for SEAVEA (EP/W007711/1). We acknowledge support from NSF Grant No. DGE-1842474 and by the NSF STAQ project (PHY-1818914).We acknowledge support from D-Wave Systems, CBKSciCon Ltd., Atos, Intel and Zapata.

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Publication: Kirby, William M., and Peter J. Love. "Contextuality test of the nonclassicality of variational quantum eigensolvers." Physical review letters 123.20 (2019): 200501.
Kirby, William M., and Peter J. Love. "Classical simulation of noncontextual Pauli Hamiltonians." Physical Review A 102.3 (2020): 032418.
Kirby, William M., Andrew Tranter, and Peter J. Love. "Contextual subspace variational quantum eigensolver." Quantum 5 (2021): 456.?
Weaving, T. J., Ralli, A., Kirby, W. M., Tranter, A., Love, P. J., & Coveney, P. V. (2022). A stabilizer framework for Contextual Subspace VQE and the noncontextual projection ansatz. arXiv preprint arXiv:2204.02150.
Ralli, A., Weaving, T., Tranter, A., Kirby, W. M., Love, P. J., & Coveney, P. V. (2022). Unitary Partitioning and the Contextual Subspace Variational Quantum Eigensolver. arXiv preprint arXiv:2207.03451.

Presenters

  • Peter J Love

    • Tufts University

Authors

  • Peter J Love

    • Tufts University

  • William M Kirby

    • Tufts University

  • Andrew Tranter

    • Quantinuum

  • Alexis P Ralli

    • University College London

  • Timothy Weaving

    • University College London

  • Peter V Coveney

    • University College London