Spontaneous symmetry breaking in a two-doublet lattice Higgs model

TL;DR

This paper investigates a two-doublet SU(2) lattice gauge theory, mapping its phase diagram and identifying spontaneous symmetry breaking and Goldstone bosons through nonperturbative numerical simulations.

Contribution

It provides the first detailed phase diagram of a two-doublet lattice Higgs model and confirms spontaneous symmetry breaking patterns via numerical evidence.

Findings

Identification of phase transitions separating different regions

Observation of spontaneous symmetry breaking in certain parameter regions

Detection of Goldstone bosons confirming symmetry breaking

Abstract

An SU(2) lattice gauge theory with two doublets of complex scalar fields is considered. All continuous symmetries are identified and, using the nonperturbative methods of lattice field theory, the phase diagram is mapped out by direct numerical simulation. Two-doublet models contain phase transitions that separate qualitatively distinct regions of the parameter space. In some regions global symmetries are spontaneously broken. For some special choices of the model parameters, the symmetry-breaking order parameter is calculated. The pattern of symmetry breaking is verified further through observation of Goldstone bosons.