Double sine-Gordon model revisited

TL;DR

This paper reexamines the mass spectrum of the double sine-Gordon model using numerical methods, confirming previous results and challenging recent semiclassical claims.

Contribution

It provides a numerical validation of the original mass spectrum results and critically assesses semiclassical techniques in the double sine-Gordon model.

Findings

Numerical results support the original mass spectrum.

Semiclassical soliton form factor methods are inconsistent with numerical data.

Theoretical discussion clarifies the validity of different approaches.

Abstract

We reconsider the mass spectrum of double sine-Gordon theory where recent semiclassical results called into question the previously accepted picture. We use the Truncated Conformal Space Approach (TCSA) to investigate the claims. We demonstrate that the numerics supports the original results, and strongly disagrees with those obtained from semiclassical soliton form factor techniques. Besides the numerical analysis, we also discuss the underlying theoretical arguments.