Efeitos não-lineares em sistemas dissipativos

AUTOR(ES)
DATA DE PUBLICAÇÃO

1991

RESUMO

A non-linear quantum transport theory for many-body systems arbitrarily away from equilibrium is elaborated using Zubarev s non-equilibrium statistical operator method. It is described an iterative method that allows to organize the collision integrals with memory in a series of partial contribution of increasing power in the intensity of the interaction, leading to a nonlinear relaxation theory based on instantaneous collision integrals. In the lowest order, the so called linear theory of relaxation corresponds to the Markovian approximation to the relaxation processes, and memory effects are at least of third order in the intensities of the interaction. The method is applied for the treatment of non-linear effects in n-doped polar semiconductors, where is shown that through free carrier absorption in laser photoexcitation processes, LO phonons are produced in excess of equilibrium in a privileged region of the reciprocal space. Non-linear effects are important at high levels of photoexcitation, where are responsible for the channeling of energy from the pumped modes to the modes at the edge of the Brillouin zone, whose population grows enormously, following a phenomenon akin to a non-equilibrium Bose-Einstein condensation

ASSUNTO(S)

estatistica quantica termodinamica

ACESSO AO ARTIGO

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