Understanding the High-Energy Limit of Quantum Field Theory

Explore the high-energy limit of quantum field theory in this comprehensive lecture that examines one of physics' most enduring open problems. Delve into the regime where center of mass energy hierarchically exceeds momentum exchange, a critical area in both Yang-Mills theory and gravity with significant phenomenological and formal implications. Learn how this "Regge" limit dominates cross sections at particle colliders in Yang-Mills theory and leads to black hole formation in gravitational contexts. Discover the challenges posed by naive calculations that appear to violate unitarity and examine how recent advances in effective field theory have provided new insights and breakthrough results. Gain understanding of why this century-old problem remains at the forefront of theoretical physics research, affecting everything from non-Fermi liquids to fundamental questions about the nature of quantum field theory itself.