Inflation and nonequilibrium thermodynamics for the fluctuations in the infrared sector - art. no. 087301

In the framework of inflationary cosmology I study some aspects of nonequil ibrium thermodynamics for the matter held fluctuations. The thermodynamic a nalysis is developed for de Sitter and power-law expansions of the universe . In both cases, I find that the heat capacity is negative leading respecti vely, to exponential and superexponential growth for the number of states i n the infrared sector for de Sitter and power-law expansions of the univers e. The spectrum for the matter field fluctuations can be understood from th e background effective temperature at the horizon entry.