Asymptotic behavior of the warm inflation scenario with viscous pressure

Abstract

We analyze the dynamics of models of warm inflation with general dissipative effects. We consider phenomenological terms both for the inflaton decay rate and for viscous effects within matter.We provide a classification of the asymptotic behavior of these models and show that the existence of a late-time scaling regime depends not only on an asymptotic behavior of the scalar field potential, but also on an appropriate asymptotic behavior of the inflaton decay rate. There are scaling solutions whenever the latter evolves to become proportional to the Hubble rate of expansion regardless of the steepness of the scalar field exponential potential. We show from thermodynamic arguments that the scaling regime is associated to a power-law dependence of the matter-radiation temperature on the scale factor, which allows a mild variation of the temperature of the matter/radiation fluid. We also show that the late time contribution of the dissipative terms alleviates the depletion of matter, and increases the duration of inflation. PACS numbers: 98.80.Cq, 47.75+f

Warm Inflationary Universe Models

“…In the case of warm inflation it has been proposed that the inflaton can excite a heavy field and trigger the decay of the latter into light fields (Berera & Ramos, 2003;2005a). Recently, a detailed analysis of the dynamics of warm inflation with viscous pressure showed that when Π = 0 the inflationary region takes a larger portion of the phase space associated to the autonomous system of differential equations than otherwise (Mimoso et al, 2006). It then follows that the viscous pressure facilitates inflation and lends support to the warm inflationary scenario.…”

Warming up D3 brane motion in the background of D5 brane and inflation

“…At this epoch, the universe stops inflating and smoothly enters into a radiation dominated Big Bang phase [56,57]. The matter components of the universe are created by the decay of either the dominant radiation field or the remaining inflationary field [58].…”

Arbitrary scalar-field and quintessence cosmological models

“…In [79], a phase-plane analysis was performed of the complete dynamical system corresponding to a flat FRW cosmological models with a perfect fluid and a self-interacting scalar field and it was shown that every positive and monotonous potential which is asymptotically exponential yields a scaling solution as a global attractor. The dynamics of models of warm inflation with general dissipative effects was also extensively analyzed [80,81], and a mechanism that generates the exact solutions of scalar-field cosmologies in a unified way was also investigated.…”