LONG-RANGE CORRELATIONS IN BOLTZMANN-LANGEVIN MODEL

The average phase-space density described by the Boltzmann-Langevin mo del can largely deviate from the one provided by the Boltzmann-Uhling- Uhlenbeck model, due to the non-linear evolution of density fluctuatio ns. This aspect is investigated for long-wavelength, small density flu ctuations in the framework of a memory incorporated Boltzmann-Langevin model. It is shown that the correlations associated with density fluc tuations yield a collision term describing coupling between the collec tive vibrations and the single-particle degrees of freedom, which may play an important role in damping of collective motion in both the sta ble and unstable regions.