Scattering amplitudes and their hidden symmetries

by Simon Caron-Huot (Niels Bohr International Academy and Discovery Centre, Copenhagen)

Monday 23 Jun 2014, 14:00 → 15:00 Europe/Zurich

EPFL, Cubotron 727

Physical systems that possess unexpected, or ‘hidden,’ symmetries have often played an important role in physics, beginning with the classical Kepler problem and the Laplace-Runge-Lenz vector which ensures the closure of planetary orbits. In this talk I will argue that precisely the same symmetry underlies the integrability of a unique four-dimensional quantum field theory, which is a maximally supersymmetric cousin of the strong interaction that contains both massless and massive particles. I will review some of its implications, in particular how it has led to the exact computation of the four- and five-particles massless amplitudes in this model at all values of the coupling. I will also present new applications involving the massive particles, including a somewhat unorthodox calculation of the hydrogen atom spectrum based on Regge theory, which allows for an exact treatment of multi-particle and relativistic effects in this model at both weak and strong coupling.