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arXiv · 2107.07922

Thermal coupled cluster theory for SU(2) systems

Gaurav Harsha·Yi Xu·Thomas M. Henderson·Gustavo E. Scuseria
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Abstract

Coupled cluster (CC) has established itself as a powerful theory to study correlated quantum many-body systems. Finite-temperature generalizations of CC theory have attracted considerable interest and have been shown to work as nicely as the ground-state theory. However, most of these recent developments address only fermionic or bosonic systems. The distinct structure of the $su(2)$ algebra requires the development of a similar thermal CC theory for spin degrees of freedom. In this paper, we provide a formulation of our thermofield-inspired thermal CC for SU(2) systems. We apply the thermal CC to the Lipkin-Meshkov-Glick system as well as the one-dimensional transverse field Ising model as benchmark applications to highlight the accuracy of thermal CC in the study of finite-temperature phase diagrams in SU(2) systems.

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Gaurav Harsha, Yi Xu, Thomas M. Henderson, Gustavo E. Scuseria. 2021-07-16. Thermal coupled cluster theory for SU(2) systems. https://doi.org/10.1103/physrevb.105.045125

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