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QI: Fachverband Quanteninformation

QI 30: Quantum Algorithms

QI 30.3: Talk

Thursday, March 9, 2023, 15:15–15:30, B305

Excitations of Quantum Many-Body Systems via Purified Ensembles: A Unitary-Coupled-Cluster-based Approach — Carlos L. Benavides-Riveros^1,2, Lipeng Chen², Christian Schilling^3,4, •Sebastián Mantilla², and Stefano Pittalis⁵ — ¹Pitaevskii BEC Center, CNR-INO and Dipartimento di Fisica, Università di Trento, Trento, Italy. — ²Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — ³Munich Center for Quantum Science and Technology (MCQST), München, Germany — ⁴Ludwig-Maximilians-Universität München, München, Germany — ⁵CNR-Istituto Nanoscienze, Modena, Italy

State-average calculations based on 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.

The talk is based on: Phys. Rev. Lett. 129, 066401 (2022).