electron systems at nonzero temperatures. For this purpose, we make use of the thermofield
dynamics, which allows for a compact wave function representation of the thermal density
matrix, and extend our recently developed framework (J. Chem. Phys. 2019, 150, 154109,
DOI: 10.1063/1.5089560) to parametrize the so-called thermal state using an exponential
ansatz with cluster operators that create thermal quasiparticle excitations on a mean-field …