Scattering phase shift determinations from a two-scalar field theory

Abstract

A field theory involving two interacting scalar fields, previously studied by Rummukainen and Gottlieb, is revisited. Our study is not restricted to the limit of large quartic couplings, and a Symanzik-improved action is used so that continuum dispersion relations work well. The Metropolis method, combined with a local microcanonical updating algorithm, is employed in our Monte Carlo calculations. Isotropic lattices ranging from 163 ×48 to 533 ×48 are used, and scattering phase shifts are determined using a Lüscher analysis with multiple partial waves.