New cosmological solutions from type II de-Sitter gaugings in 4D $N=4$ gauged supergravity

TL;DR

This paper presents new cosmological solutions in 4D N=4 supergravity that interpolate between dS2×S2 and dS4 spacetimes, featuring a non-zero dilaton and unique to type II de-Sitter gaugings, expanding the landscape of supergravity cosmologies.

Contribution

It introduces novel cosmological solutions in 4D N=4 supergravity with type II de-Sitter gaugings, involving a single U(1) factor and a non-zero dilaton, differing from previous solutions.

Findings

Solutions interpolate between dS2×S2 and dS4 spacetimes.

Solutions involve only a single U(1) factor from electric or magnetic gaugings.

Solutions feature a non-zero dilaton and are specific to type II de-Sitter theories.

Abstract

In this work, which is a follow-up of arXiv:2102.06512, we document new cosmological solutions from four-dimensional $N=4$ matter-coupled supergravity. The solutions smoothly interpolate between a $dS_2\times S^2$ spacetime at $t\rightarrow -\infty$ and a $dS_4$ spacetime at $t\rightarrow +\infty$ and arise from the second-order equations of motion. Unlike the previously reported solutions in arXiv:2102.06512 that involve the diagonal $U(1)$ subgroup of both the electric and magnetic factors in the gauging, these solutions only require a single $U(1)$ factor from either the electric or magnetic part. Two additional features of these solutions that distinguish them from the previously presented solutions are the nonvanishing value of the dilaton $\phi$ and the fact that they are only admitted by the type II de-Sitter gauged theories.