Research in the Particle Theory group
The holographic correspondence between string theories and large-N quantum field theories has been a powerful tool for extracting the physics of infinitely strongly coupled QFTs using classical (super-)gravity. It has long been expected that a different limit, involving large-N QFT's with weak or finite coupling will provide an insight into dual stringy versions of gravity with a tower of light higher spin fields. The duality between higher spin theories of gravity in Anti-de-Sitter spacetimes and known large-N QFTs in two and three dimensions is a fascinating arena for explorations in this direction.
The main topics being investigated at present in Swansea include properties of black hole like objects in higher spin theories in three dimensions and their relation to calculable observables in the dual two-dimensional CFTs, such as thermodynamics and entanglement entropy. This is a fascinating subject of study since black holes in higher spin theories appear to be fundamentally different from their GR cousins (with no notion of an event horizon) and yet share the thermodynamic properties of conventional black holes. Remarkably the higher spin black holes also appear to describe RG flows between 2d CFT's with different (W-algebra) symmetries, with connections to the study of integrable systems. Work in these directions is being pursued in collaboration with PhD students and the group at IISc Bangalore.