Fluctuation-induced Nambu-Goldstone bosons in a Higgs-Josephson model

TL;DR

This paper introduces a novel fluctuation mechanism in Higgs-Josephson models where perturbative fluctuations induce massless Nambu-Goldstone bosons from massive ones, revealing complex symmetry-breaking phenomena.

Contribution

It demonstrates how fluctuations can restore massless bosons in a Higgs-Josephson system with broken rotational symmetry, highlighting a new fluctuation-induced symmetry restoration mechanism.

Findings

Fluctuations can turn massive bosons into massless Nambu-Goldstone bosons.

The model exhibits a first-order transition at the critical point.

Finite temperature effects increase the number of massless bosons.

Abstract

We present a new mechanism of fluctuation-induced Nambu-Goldstone bosons in a scalar field theory of Higgs-Josephson systems. We consider a simple scalar field model with $U(1)^n$ rotational symmetry. When there is an interaction which violates the rotational symmetry, the Nambu-Goldstone bosons become massive and massless bosons are concealed. We present a model where the massive boson becomes a massless boson as a result of the perturbative fluctuation. In our model the ${\bf Z}_2$-symmetry associated with the chirality is also broken. The transition occurs as a (weak) first-order transition at the critical point. The ground state at absolute zero will flow into the state with more massless bosons due to fluctuation effects at finite temperature.