I have been a Professor of Physics at the University of Barcelona since 1991. I have also held several Visiting Professor positions at different universities such as Università di Firenze, Queens and City College of University of New York, Yukawa Institute at Kyoto, Toho University, University of Texas at Austin, Research Institute for Mathematical Sciences of University of Kyoto, Theory Group at CERN, University of Miami, Institute for Theoretical Physics KU Leuven, Centro de Estudios Científicos en Valdivia, Perimeter Institute, Tokyo Institute of Technology, High Energy Accelerator Research Organization (KEK) at Tsukuba, University of Miami, Universidad Católica Santiago de Chile, Australian National University at Canberra, University of Groningen and Universidad Austral de Chile at Valdivia.