Higgs mode in (2+1)-dimensional O(2) model

In this paper, we investigate the spectral functions of the Higgs mode in O(2) model, which can be experimentally realized in a two-dimensional Bose gas. Zero temperature limit is considered. Our calculation fully includes the 2-loop contributions. Peaks show up in the spectral functions of both the longitudinal and the scalar susceptibilities. Thus, this model cannot explain the disappearance of the response at the weak interaction limit. Neither it can explain the similarity between the longitudinal and the scalar susceptibilities in the visibility of the Higgs mode. A possible lower peak at about 2m(sigma) is also noted.

Automated summary

This paper investigates the spectral functions of the Higgs mode in the O(2) model, showing that it cannot explain the disappearance of the response at the weak interaction limit or the similarity between the longitudinal and scalar susceptibilities in the visibility of the Higgs mode. A possible lower peak at about 2m(σ) is also noted.