Worse than a big rip?

TL;DR

This paper investigates a novel finite-time future singularity caused by a generalized phantom Chaplygin gas, contrasting it with the big rip, and explores its occurrence in brane-world scenarios with a dual gas.

Contribution

It introduces a new type of finite-scale-factor singularity from a generalized phantom Chaplygin gas and examines its presence in brane-world models with a dual gas satisfying the null energy condition.

Findings

Finite-time singularity occurs at finite scale factor.

Dual of the generalized phantom Chaplygin gas satisfies the null energy condition.

Singularity appears in brane-world scenarios with dual gas.

Abstract

We show that a generalised phantom Chaplygin gas can present a future singularity in a finite future cosmic time. Unlike the big rip singularity, this singularity happens for a finite scale factor, but like the big rip singularity, it would also take place at a finite future cosmic time. In addition, we define a dual of the generalised phantom Chaplygin gas which satisfies the null energy condition. Then, in a Randall-Sundrum 1 brane-world scenario, we show that the same kind of singularity at a finite scale factor arises for a brane filled with a dual of the generalised phantom Chaplygin gas.