Southwest Quantum Information and Technology

Measurement reduction in variational quantum algorithms

Presenting Author: Andrew Zhao, University of New Mexico CQuIC
Contributing Author(s): Andrew Tranter, William M. Kirby, Shu Fay Ung, Akimasa Miyake, Peter J. Love

Variational quantum algorithms are promising applications of noisy intermediate-scale quantum (NISQ) computers. These algorithms consist of a number of separate prepare-and-measure experiments that estimate terms in the Hamiltonian. The number of separate measurements required can become overwhelmingly large for problems at the scale of NISQ hardware that may soon be available. We approach this problem from the perspective of contextuality, and use unitary partitioning to define VQE procedures in which additional unitary operations are appended to the ansatz preparation circuit to reduce the number of terms one needs to measure. This approach may be tuned to hardware specifications in order to use all coherent resources available after ansatz preparation. We investigate this technique for a variety of Hamiltonian classes, in particular the electronic structure Hamiltonian from quantum chemistry.

Read this article online: arxiv.org/abs/1908.08067

(Session 5 : Saturday from 5:00pm - 7:00pm)