TY - JOUR
T1 - Radiative thermalization in semiclassical simulations of light-matter interaction
AU - Gadea, Esteban D.
AU - Bustamante , Carlos M.
AU - Todorov, Tchavdar N.
AU - Scherlis, Damian A.
PY - 2022/4/1
Y1 - 2022/4/1
N2 - Prediction of the equilibrium populations in quantum dynamics simulations of molecules exposed to black-body radiation has proved challenging for semiclassical treatments, with the usual Ehren- fest and Maxwell-Bloch methods exhibiting serious failures. In this context, we explore the behavior of a recently introduced semiclassical model of light-matter interaction derived from a dissipative Lagrangian [Phys. Rev. Lett. 126, 087401 (2021)]. It is shown that this model reproduces the Boltzmann populations for two-level systems, predicting the black-body spectra in approximate agreement with Planck’s distribution. In multilevel systems, small deviations from the expected oc- cupations are seen beyond the first excited level. By averaging over fast oscillations, a rate equation is derived from the dissipative equation of motion that makes it possible to rationalize these devi- ations. Importantly, it enables us to conclude that this model will produce the correct equilibrium populations provided the occupations of the lowest levels remain close to unity, a condition satisfied at low temperature or small excitations.
AB - Prediction of the equilibrium populations in quantum dynamics simulations of molecules exposed to black-body radiation has proved challenging for semiclassical treatments, with the usual Ehren- fest and Maxwell-Bloch methods exhibiting serious failures. In this context, we explore the behavior of a recently introduced semiclassical model of light-matter interaction derived from a dissipative Lagrangian [Phys. Rev. Lett. 126, 087401 (2021)]. It is shown that this model reproduces the Boltzmann populations for two-level systems, predicting the black-body spectra in approximate agreement with Planck’s distribution. In multilevel systems, small deviations from the expected oc- cupations are seen beyond the first excited level. By averaging over fast oscillations, a rate equation is derived from the dissipative equation of motion that makes it possible to rationalize these devi- ations. Importantly, it enables us to conclude that this model will produce the correct equilibrium populations provided the occupations of the lowest levels remain close to unity, a condition satisfied at low temperature or small excitations.
U2 - 10.1103/PhysRevA.105.042201
DO - 10.1103/PhysRevA.105.042201
M3 - Article
SN - 1050-2947
VL - 105
JO - Physical Review A (Atomic, Molecular, and Optical Physics)
JF - Physical Review A (Atomic, Molecular, and Optical Physics)
M1 - 042201
ER -