Momentum spread of spontaneously decaying cold gas in thermal radiation
Abstract
We study the quantum dynamics of the centerofmass momentum distribution for the populations of a cold gas with twolevel system undergoing spontaneous decay and coupled to a Markovian thermal reservoir at arbitrary temperature. We derive the momentumconvolutionless coupled equations for momentum Fourier transform of the populations which can be easily solved numerically and analytically for a specific internal scheme and for zerotemperature cases. The time and momentum evolutions of the populations are obtained by inverse Fourier transform. The momentum spread and the centerofmass entropy across one momentum dimension are computed and compared for different internal schemes, between zerotemperature and finitetemperature cases and between π and σ_{±} transitions. For initial subrecoil momentum width, the σ_{±} transition displays a twopeak feature. Our results well describe the momentum spread dynamics of cold gas in thermal radiation at early time and complement the results based on FokkerPlanck equation.
 Publication:

Physical Review A
 Pub Date:
 December 2002
 DOI:
 10.1103/PhysRevA.66.063413
 Bibcode:
 2002PhRvA..66f3413O
 Keywords:

 42.50.Vk;
 42.50.Lc;
 Mechanical effects of light on atoms molecules electrons and ions;
 Quantum fluctuations quantum noise and quantum jumps