Collisional equilibrium, particle production, and the inflationary universe

Winfried Zimdahl, Josep Triginer, Diego Pavón

Research output: Contribution to journalArticleResearchpeer-review

33 Citations (Scopus)


Particle production processes in the expanding universe are described within a simple kinetic model. The equilibrium conditions for a Maxwell-Boltzmann gas with variable particle number are investigated. We find that radiation and nonrelativistic matter may be in equilibrium at the same temperature provided the matter particles are created at a rate that is half the expansion rate. Using the fact that the creation of particles is dynamically equivalent to a nonvanishing bulk pressure we calculate the back reaction of this process on the cosmological dynamics. It turns out that the `adiabatic’ creation of massive particles with an equilibrium distribution for the latter necessarily implies power-law inflation. Exponential inflation in this context is shown to become inconsistent with the second law of thermodynamics after a time interval of the order of the Hubble time. © 1996 The American Physical Society.
Original languageEnglish
Pages (from-to)6101-6110
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number10
Publication statusPublished - 1 Jan 1996


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