On-shell methods in Quantum Field Theory

          @misc{ pirsa_PIRSA:08120055,
            doi = {10.48660/08120055},
            url = {https://pirsa.org/08120055},
            author = {Kiemaier, Michael},
            keywords = {Quantum Fields and Strings},
            language = {en},
            title = {On-shell methods in Quantum Field Theory},
            publisher = {Perimeter Institute},
            year = {2008},
            month = {dec},
            note = {PIRSA:08120055 see, \url{https://pirsa.org}}
          }
          

Abstract

The efficient computation of scattering amplitudes in quantum field theory has many important applications, ranging from the computation of QCD backgrounds at the LHC to the study of the perturbative finiteness of N=8 supergravity. \'On-shell methods\' are a crucial ingredient in the computation of gauge theory and gravity amplitudes because they are far more efficient than traditional Feynman diagram techniques. I give an introduction to the basic concepts used in this field. I explain one particularly elegant method, the MHV vertex expansion, and outline how we recently proved the validity of this expansion in N=4 Super Yang-Mills Theory.