We propose the simulation of quantum-optical systems in the ultrastrong-coupling regime using a variational quantum algorithm. More precisely, we introduce a short-depth variational form to prepare the ground state of the multimode Dicke model on a quantum processor and present proof-of-principle results obtained using an IBM device. We moreover provide an algorithm for characterizing the ground state by Wigner state tomography. Our work is a first step toward digital quantum simulation of light-matter systems with potential applications to few-impurity spin-boson models.

• Received 27 September 2019
• Revised 24 June 2020
• Accepted 14 August 2020

DOI:https://doi.org/10.1103/PhysRevResearch.2.033364

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society