Bulat Farkhtdinov, Multiparticle production in λϕ^4 theory

ITMP seminar, Mar 29, 2023
Speaker: Bulat Farkhtdinov, INR RAS & MIPT, Moscow
Title: Multiparticle production in λϕ^4 theory: method of singular solutions and numerical results
Abstract: We consider the creation of n≫1 scalar bosons from several colliding ones in the (3+1)-dimensional λϕ^4 theory without spontaneous symmetry breaking. When coupling λ is weak, probabilities of these processes can be calculated using the semiclassical method of singular solutions. We numerically implemented this method and for the first time obtained reliable results for probabilities in the region of an exceptionally large number of particles in the final state λn≫1, where probabilities decrease exponentially with growth of n. The exponent depends linearly on n, and its slope depends on the average kinetic energy ε of the created particles. In the opposite limit of λn≪1, our numerical data agree with the known tree-level results, and data in the region λn~1 interpolate between these two limits. Overall, this proves exponential suppression of the multiparticle production probability at n≫1 and arbitrary ε in the unbroken theory. In the talk I will cover both the method of singular solutions itself, its numerical implementation, and the obtained results.