Time-dependent backgrounds from supergravity with gauged non-compact R-symmetry

TL;DR

This paper constructs a broad class of time-dependent supergravity backgrounds with de Sitter asymptotics, including multi-centered charged black holes, and explores their relations via T-duality and dimensional reduction.

Contribution

It introduces new time-dependent solutions in supergravity with gauged non-compact R-symmetry, including multi-centered black holes and their dimensional reductions, linking them through T-duality.

Findings

Constructed time-dependent de Sitter backgrounds solving supergravity equations.

Presented multi-centered charged black hole solutions with hyper-Kähler spatial parts.

Demonstrated relations between four- and five-dimensional solutions via T-duality.

Abstract

We obtain a general class of time-dependent, asymptotically de Sitter backgrounds which solve the first order bosonic equations that extremize the action for supergravity with gauged non-compact $R$-symmetry. These backgrounds correspond only to neutral fields with the correct sign of kinetic energy. Within N=2 five-dimensional supergravity with vector-superfields we provide examples of multi-centered charged black holes in asymptotic de Sitter space, whose spatial part is given by a time-dependent hyper-K\"ahler space. Reducing these backgrounds to four dimensions yields asymptotically de Sitter multi-centered charged black hole backgrounds and we show that they are related to an instanton configuration by a massive T-duality over time. Within N=2 gauged supergravity in four (and five)-dimensions with hyper-multiplets there could also be neutral cosmological backgrounds that are regular and correspond to the different de Sitter spaces at early and late times.