Thermofield theory for finite-temperature coupled cluster

Gaurav Harsha; Thomas M. Henderson; Gustavo E. Scuseria

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arXiv · 1907.11286

Thermofield theory for finite-temperature coupled cluster

Gaurav Harsha·Thomas M. Henderson·Gustavo E. Scuseria

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Abstract

We present a coupled cluster and linear response theory to compute properties of many-electron systems at non-zero temperatures. For this purpose, we make use of the thermofield dynamics, which allows for a compact wavefunction representation of the thermal density matrix, and extend our recently developed framework [J. Chem. Phys. 150, 154109 (2019)] to parameterize the so-called thermal state using an exponential ansatz with cluster operators that create thermal quasiparticle excitations on a mean-field reference. As benchmark examples, we apply this method to both model (one-dimensional Hubbard and Pairing) as well as ab-initio (atomic Beryllium and molecular Hydrogen) systems, while comparing with exact results.

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Gaurav Harsha, Thomas M. Henderson, Gustavo E. Scuseria. 2019-07-25. Thermofield theory for finite-temperature coupled cluster. https://arxiv.org/abs/1907.11286

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