My main field of research is String Theory, with a particular emphasis in black hole physics, cosmology and particle physics.

One of the topics I have been interested is that of black holes and branes in string theory. These objects can be described in the supergravity low energy description of string theory. I have been particularly interested in understanding the microscopic origin of the Hawking-Bekenstein entropy, the interaction of black holes with external fields and their formation.

In the past years I have also been particularly interested in studying string theory in time dependent geometries. Our goal is to define a theory of gravity in an expanding universe, particularly near cosmological singularities, where quantum effects are important. Ultimately we expect to derive from string theory a phenomenological model for the observed universe. You can see my lectures at the 2003 European RTN Winter School in Torino, Italy. This work was awarded the 2004 Gulbenkian Science Prize. We also proposed an alternative to the chronology protection conjecture put forward by Hawking. You can listen to a talk I gave on the subject at the 2005 Workshop on Gravitational Aspects of String Theory at the Fields Institute in Toronto, Canada.

More recently, my research has been focusing on the AdS/CFT duality. I am particularly interested on scattering at high energies in Anti de Sitter spaces and on its implicatons to the dual CFT and to high energy processes in QCD. You can download the talk I gave on the subject at the 2007 Pre-strings Conference held in Granada, Spain.