Barotropic FRW cosmologies with Chiellini damping in comoving time

TL;DR

This paper explores barotropic FRW cosmologies with Chiellini damping, revealing that in the radiation-dominated case, solutions in comoving time mirror those with Chiellini dissipative scale factors in conformal time, linked through the Ermakov equation.

Contribution

It demonstrates the equivalence of certain FRW cosmologies with Chiellini damping in different time frameworks and provides new solutions for zero cosmological constant cases.

Findings

Radiation-dominated solutions match between comoving and conformal time frameworks.

Derived new particular solutions for zero cosmological constant.

Linked solutions through the Ermakov equation.

Abstract

For non-zero cosmological constant Lambda, we show that the barotropic FRW cosmologies as worked out in the comoving time lead in the radiation-dominated case to scale factors of identical form as for the Chiellini dissipative scale factors in conformal time obtained recently by us in Phys. Lett. A 379 (2015) 882-887. This is due to the Ermakov equation which is obtained in this case. For zero cosmological constant, several textbook solutions are provided as particular cases of Lambda different from zero.