Thermofield dynamics is an exactly correct formulation of quantum mechanics at finite temperature in which a wavefunction is governed by an effective temperature-dependent quantum Hamiltonian. The optimized mean trajectory (OMT) approximation allows the calculation of spectroscopic response functions from trajectories produced by the classical limit of a mapping Hamiltonian that includes physical nuclear degrees of freedom and other effective degrees of freedom representing discrete vibronic states. Here, we develop a thermofield OMT (TF-OMT) approach in which the OMT procedure is applied to a temperature-dependent classical Hamiltonian determined from the thermofield-transformed quantum mapping Hamiltonian. Initial conditions for bath nuclear degrees of freedom are sampled from a zero-temperature distribution. Calculations of two-dimensional electronic spectra and two-dimensional vibrational–electronic spectra are performed for models that include excitonically coupled electronic states. The TF-OMT calculations agree very closely with the corresponding OMT results, which, in turn, represent well benchmark calculations with the hierarchical equations of motion method.
Two-dimensional vibronic spectroscopy with semiclassical thermofield dynamics
Note: This paper is part of the JCP Special Topic on Time-Resolved Vibrational Spectroscopy.
Kritanjan Polley, Roger F. Loring; Two-dimensional vibronic spectroscopy with semiclassical thermofield dynamics. J. Chem. Phys. 28 March 2022; 156 (12): 124108. https://doi.org/10.1063/5.0083868
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