Old Journal Club: ‘Particle Spectrum in Quantum Field Theory’

Alejandro Puga (IFT) will present “Particle Spectrum in Quantum Field Theory”  de Alexander M. Polyakov (JETP Lett. 20 (1974) 194-195)

Abstract: We investigate the nonperturbative structure of quantum field theories and its consequences for the physical spectrum of excitations. Emphasis is placed on the role of instantons—topologically nontrivial field configurations—which contribute essentially to tunneling processes and mass generation beyond perturbation theory. The analysis demonstrates how instanton effects modify correlation functions and lead to qualitatively new features in the particle spectrum, highlighting the deep connection between topology, symmetry, and dynamics in quantum field theory.