KINETIC-THEORY FOR NONGEODESIC PARTICLE MOTION - SELF-INTERACTING EQUILIBRIUM STATES AND EFFECTIVE VISCOUS-FLUID PRESSURES

The particles of a classical relativistic gas are assumed to move unde r the influence of a quasilinear tin the particle 4-momenta), self-int eracting force in between elastic, binary collisions. This force, whic h is completely fixed by the equilibrium conditions of the gas, gives rise to an effective viscous pressure on the quid phenomenological lev el. Earlier results concerning the possibility of accelerated expansio n of the universe due to cosmological particle production are reinterp reted. A phenomenon such as power-law inflation may be traced back to specific self-interacting forces keeping the particles of a gas univer se in states of generalized equilibrium.