Speaker
Description
Inspired by quantum-mechanical Landau method, we propose a new perturbatively exact relation between scattering amplitudes in bosonic theories and vacuum-to-vacuum transition amplitudes in the same theories with vanishingly weak sources on singular backgrounds. We argue that the new relation automatically resums the powers of gn in perturbative amplitudes of n quanta production, where g is a coupling constant. In this way, one can describes double-scaling limits g->0, gn=const of n-particle production in quantum field theory and of vacuum-to-nth excited state transitions in quantum mechanics. In the lowest semiclassical order, our relation reproduces D.T. Son's method of singular solutions and proves Rubakov-Son-Tinyakov conjecture. We illustrate it in the model of anharmonic oscillator and discuss its application to multiparticle production in the scalar lambda phi^4 theory.
