$dS_4$ vacua from matter-coupled 4D N=4 gauged supergravity

Abstract

We study $dS_4$ vacua within matter-coupled $N=4$ gauged supergravity in the embedding tensor formalism. We derive a set of conditions for the existence of $dS_4$ solutions by using a simple ansatz for solving the extremization and positivity of the scalar potential. We find two classes of gauge groups that lead to $dS_4$ vacua. One of them consists of gauge groups of the form $G_{\textrm{e}}\times G_{\textrm{m}}\times H$ with $H$ being a compact group and $G_{\textrm{e}}\times G_{\textrm{m}}$ a non-compact group with $SO(3)\times SO(3)$ subgroup and dynonically gauged. These gauge groups are the same as those giving rise to maximally supersymmetric $AdS_4$ vacua. The $dS_4$ and $AdS_4$ vacua arise from different coupling ratios between $G_{\textrm{e}}$ and $G_{\textrm{m}}$ factors. Another class of gauge groups is given by $SO(2,1)_{\textrm{e}}\times SO(2,1)_{\textrm{m}}\times G_{\textrm{nc}}\times G'_{\textrm{nc}}\times H$ with $SO(2,1)$, $G_{\textrm{nc}}$ and $G'_{\textrm{nc}}$ dyonically gauged. We explicitly check that all known $dS_4$ vacua in $N=4$ gauged supergravity satisfy the aforementioned conditions, hence the two classes of gauge groups can accommodate all the previous results on $dS_4$ vacua in a simple framework. Accordingly, the results provide a new approach for finding $dS_4$ vacua. In addition, relations between the embedding tensors for gauge groups admitting $dS_4$ and $dS_5$ vacua are studied, and a new gauge group, $SO(2,1)\times SO(4,1)$, with a $dS_4$ vacuum is found by applying these relations to $SO(1,1)\times SO(4,1)$ gauge group in five dimensions.