Abstract

Screened modified gravity such as chameleon and symmetron gravity is a viable alternative to quintessence when addressing problems such as dark energy. To date, these theories have been largely phenomenological and few attempts at unifying them with the rest of particle physics has been made. Furthermore, these models generically require a cosmological constant in order to match observations. In this talk I will describe recent progress towards addressing these issues by presenting a globally supersymmetric framework for describing the low-energy behaviour of these theories. The inclusion of supersymmetry leads to strong restrictions on the types of models that are viable and I will describe these new features, which include density-dependent supersymmetry breaking and SUPER -screening. A cosmological constant emerges naturally within this framework at low cosmological densities. This framework can tell us a lot about potential UV completions of such theories; which ones are viable and, more importantly, which are not.