Premium
Fluctuation and Relaxation Properties of a Two‐Level‐System Influenced by a Nonstationary External Field
Author(s) -
Ponath H.E.,
Schubert M.
Publication year - 1977
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/andp.19774890607
Subject(s) - dissipative system , physics , excitation , relaxation (psychology) , quantum , biharmonic equation , field strength , field (mathematics) , scattering , raman scattering , quantum mechanics , quantum electrodynamics , condensed matter physics , raman spectroscopy , psychology , social psychology , mathematics , magnetic field , pure mathematics , boundary value problem
The structural dependence of the longitudinal and transversal relaxation times of a two‐level‐system on the transition frequency ω 0 and the temperature of the coupled dissipative system has been derived. The fluctuation operators are explicitely given in dependence on the operators and the constants of the dissipative and the two‐level‐system; the corresponding fluctuation correlators have been calculated. If additionally a time‐dependent external force F ( t ) acts on the system, then the fluctuation correlators depend on the temporal behavior of this force. Due to this effect the run of nonstationary processes which are initiated by quantum noise (e.g., scattering processes) is affected. These considerations have been applied to the case of spontaneous anti‐Stokes Raman scattering with biharmonic vibrational excitation by ultra‐short light pulses. The strength of the external force, which gives rise to an appreciable time dependence of the correlators, has been estimated.