Photon emission from translational energy in atomic collisions: A dynamic Casimir-Polder effect
- Department of Chemistry, SE 901 87 Umeaa, Umeaa University (Sweden)
It is demonstrated, using a Liouville formalism, that the relative motion of two atoms can result in the emission of photons and conversely that photons can be absorbed to excite the relative translational motion. The mechanism responsible for the energy transfer between the radiation field and the translational motion of the atoms is a dynamic version of the long-range Casimir-Polder interaction between two fixed atoms. The phenomenon is analogous to the dynamic Casimir effect discussed for moving macro- (or meso)scopic objects and we term it the dynamic Casimir-Polder effect. The absorption or emission is a two-photon process and we find that the transition probability is proportional to the spectral density of a correlation function involving the relative translational motion of two atoms. An energy transfer only occurs for photons with energies smaller than or of the same magnitude as the thermal energy. The effect provides a microscopic mechanism for establishing thermal equilibrium between the radiation field and a gas. A sufficiently large volume of gas would be perceived as a black-body radiator. Applications of the dynamic Casimir-Polder effect might be found in the microscopic description of the cosmic low-temperature black-body radiation.
- OSTI ID:
- 20717865
- Journal Information:
- Physical Review. A, Vol. 71, Issue 6; Other Information: DOI: 10.1103/PhysRevA.71.062106; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION
ATOMS
CASIMIR EFFECT
CORRELATION FUNCTIONS
ENERGY TRANSFER
LIFETIME
MULTI-PHOTON PROCESSES
PHOTOEMISSION
PHOTON EMISSION
PHOTON-ATOM COLLISIONS
PHOTONS
PROBABILITY
RADIATORS
SPECTRAL DENSITY
THERMAL EQUILIBRIUM