Thermal Casimir–Polder Forces

Abstract

AbstractThe influence of thermal photons on the Casimir–Polder force is studied. In a first approach, the thermal Casimir–Polder potential is found using time-independent perturbation theory. An atom in an energy eigenstate is seen to be subject to resonant forces due to stimulated emission and absorption of thermal photons. At thermal equilibrium, the thermal Casimir–Polder force is purely non-resonant and described by a Matsubara sum. The intertwined position- and temperature-dependences of the potential are demonstrated for an atom in front of a plate. In a second, dynamical approach, the thermal Casimir–Polder force is derived from the average Lorentz force. An initially excited atom is seen to settle into a thermal state in the long-time limit. During this process, resonant Casimir–Polder forces decay, leaving the purely non-resonant equilibrium force.KeywordsCasimir ForceThermal PhotonSpatial OscillationAtomic Transition FrequencyIncoherent SuperpositionThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.