Duality gives rise to Chaplygin cosmologies with a big rip

Abstract

We consider modifications to the Friedmann equation motivated by recent proposals along these lines pursuing an explanation to the observed late time acceleration. Here we show those modifications can be framed within a theory with self-interacting gravity, where the term self-interaction refers here to the presence of functions of ρ and p in the right hand side of the Einstein equations. We then discuss the construction of the duals of the cosmologies generated within that framework. After that we investigate the modifications required to generate generalized and modified Chaplygin cosmologies and show that their duals belong to a larger family of cosmologies we call extended Chaplygin cosmologies. Finally, by letting the parameters of those models take values not earlier considered in the literature we show some representatives of that family of cosmologies display sudden future singularities, which indicates their behavior is rather different from generalized or modified Chaplygin gas cosmologies. This reinforces the idea that modifications of gravity can be responsible for unexpected evolutionary features in the universe.

Quintom cosmology: Theoretical implications and observations

“…Specifically, in [165] a link between standard cosmology with quintessence matter and contracting cosmology with phantom, has been shown. Later on this duality was generalized into more complicated DE models, where it has been shown to exist too [166,167,168,169,170,171]. In [172,173] the authors have studied this cosmic duality and its connection to the fates of the universe, while in [174] the author has also discussed the possibility of realizing the aforementioned duality in braneworld cosmological paradigm.…”

Slow-roll inflation preceded by a topological defect phaseà laChaplygin gas

“…[22] (see also Ref. [18]) and, under suitable constraints on A 2 , B 2 , and α 2 , can depict the transition from the de Sitter-like era to the radiation dominated era. The energy density (2.5c) is the standard ΛCDM model, in which ρ r0 , ρ m0 , and ρ Λ are the energy densities of the radiation, matter, and dark energy today, respectively.…”

“…We consider the matter content of the early universe to be described by a kind of generalized Chaplygin gas (GCG) [14][15][16][17][18], which offers a smooth transition between different eras:…”

On the Generalized Chaplygin Gas: Worse Than a Big Rip or Quieter Than a Sudden Singularity?

“…13 (see also Refs. 16,17 ). In this model the universe expands until it reaches a maximum size, at which moment it freezes with an infinite energy density; for this reason this doomsday has been named big freeze singularity 7 .…”