Two-fluid solutions of particle-creation cosmologies

• Main Authors: Supriya Pan, John D. Barrow, Andronikos Paliathanasis
• Format: Article
• Language: English
• Published: SpringerOpen 2019-02-01
• Series: European Physical Journal C: Particles and Fields
• Online Access: http://link.springer.com/article/10.1140/epjc/s10052-019-6627-5

Abstract Cosmological evolution driven incorporating continuous particle creation by the time-varying gravitational field is investigated. We consider a spatially flat, homogeneous and isotropic universe with two matter fluids in the context of general relativity. One fluid is endowed with gravitationally induced “adiabatic” particle creation, while the second fluid simply satisfies the conservation of energy. We show that the dynamics of the two fluids is entirely controlled by a single nonlinear differential equation involving the particle creation rate, $$ \Gamma (t)$$ Γ(t) . We consider a very general particle creation rate, $$\Gamma (t)$$ Γ(t) , that reduces to several special cases of cosmological interest, including $$ \Gamma =$$ Γ= constant, $$\Gamma \propto 1/H^{n}$$ Γ∝1/Hn ($$n\in \mathbb {N}$$ n∈N ), $$\Gamma \propto \exp (1/H)$$ Γ∝exp(1/H) . Finally, we present singular algebraic solutions of the gravitational field equations for the two-fluid particle creation models and discuss their stability.