Excitations of Quantum Many-Body Systems via Purified Ensembles: A Unitary-Coupled-Cluster-Based Approach

Year: 2022

Authors: Benavides Riveros C.L., Chen L., Schilling C., Mantilla S., Pittalis S.

Autors Affiliation: Max Planck Institute for the Physics of Complex Systems, Ntzthnitzer Strasse 38, Dresden, 01187, Germany; INO-CNR BEC Center, Trento, I-38123, Italy; Faculty of Physics, Arnold Sommerfeld Centre for Theoretical Physics (ASC), Ludwig-Maximilians-Universitdt M

Abstract: State-average calculations based on a mixture of states are increasingly being exploited across chemistry and physics as versatile procedures for addressing excitations of quantum many-body systems. If not too many states should need to be addressed, calculations performed on individual states are also a common option. Here we show how the two approaches can be merged into one method, dealing with a generalized yet single pure state. Implications in electronic structure calculations are discussed and for quantum computations are pointed out.


Volume: 129 (6)      Pages from: 066401-1  to: 066401-7

More Information: C. L. B.-R. thanks Alexander Eisfeld, Frank Gro ss mann, and Carlo Danieli for insightful discussions, and Miguel Marques for encouragement. We acknowledge financial support from “BiGmax,” the Max Planck Society´s research network on big-data-driven materials science (C. L. B.-R.), the Max-Planck Gesellschaft via the MPI-PKS visitors program (L. C.), the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), Grant No. SCHI 1476/1-1, the Munich Center for Quantum Science and Technology and the Munich Quantum Valley, which is supported by the Bavarian State Government with funds from the Hightech Agenda Bayern Plus (C. S.), and from the MIUR PRIN Grant No. 2017RKWTMY (S. P.).
DOI: 10.1103/PhysRevLett.129.066401