11th Bologna Workshop on Conformal Field Theory and Integrable Models

Confinement of solitons in the double sine-Gordon model

2 Sept 2025, 14:00

30m

Aula Magna (Dept. of Physics and Astronomy - University of Bologna)

Poster Posters

Speaker

Sergei Rutkevich (Retired from Bergische Universität Wuppertal)

Description

The double sine-Gordon model is the non-integrable deformation of the standard sine-Gordon model caused by the cosine perturbation with the frequency reduced by the factor of 2. It was showed by Delfino and Mussardo [1], that this perturbation induces confinement of the sine-Gordon solitons, which become coupled into the ‘me- son’ bound states. I calculate [2] the meson masses in the weak confinement regime, which corresponds to the small deformation of the sine-Gordon model. It is shown in particular, that there is no qualitative difference between mesons and breathers in this regime: the sine-Gordon breathers slightly deformed by the perturbation term, smoothly transform into mesons upon increase of the sine-Gordon coupling constant.
References
[1] G. Delfino, and G. Mussardo, Nucl. Phys. B 516, 675 (1998).
[2] S. Rutkevich, SciPost Phys. 16, 042 (2024).