An earlier exact result (Phys. Rev. Lett. 55 (1985), 2273) for the free energy of an oscillatordipole interacting with the radiation field is obtained using the fluctuation-dissipation theorem. A key feature of the earlier calculation, a remarkable formula for the free energy of the oscillator, is obtained in the form of a corresponding formula for the oscillator energy. This confirms, by a longer, more conventional proof, the earlier result. An advantage of this present method is that separate contributions to the energy can be isolated and discussed. Explicit, closed-form expressions are given and the high-temperature limit is discussed. © 1988.
Publication Source (Journal or Book title)
Annals of Physics
Ford, G., Lewis, J., & O'Connell, R. (1988). Quantum oscillator in a blackbody radiation field II. Direct calculation of the energy using the fluctuation-dissipation theorem. Annals of Physics, 185 (2), 270-283. https://doi.org/10.1016/0003-4916(88)90047-4