A Department of Physics colloquium entitled “The Bootstrap Program for the Strong Force” with Professor Leonardo Rastelli, C.N. Yang Institute for Theoretical Physics, Stony Brook University.
Please note – The lecture will run from 16:00-17:00, followed by refreshments from 17:00-18:00 in the Level 2 Foyer of the Blackett Building.
Abstract
In the 1960s, the dominant approach to the strong interaction was the S-matrix bootstrap: the idea that the hadronic spectrum and scattering amplitudes could be determined from the general principles of causality and unitarity. This program culminated in the Veneziano amplitude which gave birth to string theory, but was abandoned as an approach to the strong force after the identification of Quantum Chromodynamics (QCD) as the microscopic theory of hadron physics. Yet QCD at low energies remains largely unsolved. I will describe how modern bootstrap methods, powered new theoretical insights and computational techniques, allow us to revisit this classic program with unprecedented rigor. Consistency of pion scattering — with minimal assumptions about the lightest resonances — leads to the emergence of Regge trajectories from the bootstrap bounds. The bootstrap approach becomes particularly sharp in the limit of a large number of colors. The low-lying spectrum of the extremal solutions shows a tantalizing, and still somewhat mysterious, quantitative proximity to the real-world meson masses. I will discuss what we are learning from these results and outline open questions on the path toward a bootstrap solution of large N QCD.
Biography
Leonardo Rastelli is a professor at the C.N. Yang Institute for Theoretical Physics (YITP), Stony Brook University, where he is the inaugural holder of the Renaissance Chair in Theoretical Physics. He received his Ph.D. from the Massachusetts Institute of Technology (MIT) in 2000. He was a Dicke Fellow (2000-2002) and an Assistant Professor (2002-2006) at Princeton University before joining the YITP in 2006. Rastelli is the recipient of an Outstanding Junior Investigator award, a Simons Fellowship, a Guggenheim Fellowship, a Humboldt Fellowship, and has been a Blavatnik national finalist.
Rastelli’s research interests have ranged from structural aspects of string theory to purely field-theoretic questions. He is known for his contributions to the AdS/CFT correspondence, string field theory, supersymmetric field theory and the bootstrap program. Currently, Rastelli works on a broad range of problems in theoretical physics. He is interested in developing a deeper framework for quantum field theory and quantum gravity, based on symmetry and general consistency principles, in the spirit of the bootstrap.