Southwest Quantum Information and Technology

Error mitigation of correlated electronic structure simulations on a quantum device

Presenting Author: Thomas O'Brien, Google
Contributing Author(s): Gian-Luca Anselmetti, Fotios Gkritsis, Vincent Elfving, Stefano Polla, William J. Huggins, Oumarou Oumarou, Kostyantyn Kechedzhi, Christian Gogolin, Ryan Babbush, Nicholas C. Rubin

One of the main markers of progress in the development of useful quantum computing devices is the simulation of ever more challenging physical systems. As the complexity of the physical system grows the importance of robust and scalable error mitigation strategies increases as well --- especially for near term quantum devices. Herein we push towards the full complexity demanded for real-world electronic structure simulations on quantum hardware, by simulating ground states of systems projected into a pairing subspace known as seniority zero. Studying physical simulation within the seniority zero approximation affords a computational stepping stone to a fully correlated model to validate the scalablity of recent error mitigation strategies. We examine the performance of combined variational relaxation, accounting for coherent quantum device errors, and error mitigation based on doubling quantum resources in time (echo verification). We prepare ground states of correlated electronic systems on 10-qubit systems to a typical relative accuracy of 0.45%, and achieve an up to 300-fold reduction of error over simple post-selection. Our results frame the potential of near-term quantum processors to provide computational advantages for correlated electronic structure problems.

Read this article online: Preceeding work: https://journals.aps.org/prxquantum/abstract/10.1103/PRXQuantum.2.020317, Preceeding work: https://arxiv.org/abs/2207.09479

(Session 7 : Friday from 11:30am-12:00pm)