Thermodynamic variables in the context of a nonequilibrium statistical ensemble approach

Abstract

We consider the question of the definition of thermodynamic-like variables in the context of a statistical thermodynamics, which is a large generalization of Gibbs statistical thermostatics and linear and local-equilibrium classical irreversible thermodynamics. It is based on a nonequilibrium ensemble approach known as the nonequilibrium statistical operator method. Some of these quasithermodynamic variables are characteristic of the nonequilibrium state and go to zero in the limit of local or global equilibrium, but others go over the thermodynamic variables that are present in such a limit. We consider in particular temperature-like variables for the different subsystems of the sample. For illustration we apply the theory to the study of optical properties of highly photoexcited plasma in semiconductors, following a good agreement between theory and experimental data. It is shown that high-resolution spectroscopy provides an excellent experimental testing ground for corroboration of the theoretical concepts, and a quite appropriate way for characterizing and measuring nonequilibrium thermodynamic-like variables.

Hot Electron Dynamics in Zincblende and Wurtzite GaN

“…The next kinetic stage corresponds to a description of the carriers in terms of distribution functions in single-particle band energy states. Next, under the action of Coulomb interaction and carrier±phonon collisions there follows an internal thermalization of the carriers whose nonequilibrium thermodynamic state can be characterized by the time-dependent density nt and quasi-temperature T * t [19,20]. In most cases a third kinetic stage is characterized by the mutual thermalization of carriers and optical phonons, followed by the attainment of final equilibrium with the acoustical phonons and the external thermal reservoir.…”

Dynamics of a Bose-Einstein condensate of excited magnons

“…following, respectively, Fröhlich [11] and Landsberg [53] introducing a socalled quasi-chemical potential per mode, µ * q (t), and Landau, Uhlenbeck and others (a description in [31,54]), introducing a so-called quasi-temperature (or nonequilibrium temperature) per mode [54,55], T * q (t), as it is usual in semiconductor physics [56,57].…”

Topics in Present-day Science Technology and Innovation: Ultrafast Relaxation Processes in Semiconductors

“…The characterization of the macroscopic state of the system is a crucial step in the theory. This question has been discussed elsewhere 18,19,54,55 , and, for the particular case of the HEPS in Vasconcellos et al 56 . The Figure 3 reproduces the chain of successive contracted descriptions appropriate for HEPS.…”

“…respectively, where μ e * and μ h * are the quasi-chemical potentials for electrons and for holes; we write β c * (t) = 1/k B T c * (t) introducing the carriers' quasitemperature T c * ; β q * (t) = 1/k B T q * (t) introducing the LO-phonon quasitemperature per mode (ωq is the dispersion relation) 54,72,78 , β 0 = 1/k B T 0 with T 0 being the temperature of the thermal reservoir. We indicate the corresponding macrovariables, that is, those which define the nonequilibrium thermodynamic space as † { ( ), ( ), ( ), ( ), ( ), ( ),…”