We consider the two-dimensional quantum field theory of a scalar field self-interacting via two periodic terms of frequencies $\alpha$ and $\beta$. Looking at the theory as a perturbed Sine-Gordon model, we use Form Factor Perturbation Theory to analyse the evolution of the spectrum of particle excitations. We show how, within this formalism, the non-locality of the perturbation with respect to the solitons is responsible for their confinement in the perturbed theory. The effects of the frequency ratio $\alpha/\beta$ being a rational or irrational number and the occurrence of massless flows from the gaussian to the Ising fixed point are also discussed. A generalisation of the Ashkin-Teller model and the massive Schwinger model are presented as examples of application of the formalism.
|Titolo:||Non-integrable aspects of the multi-frequency sine-Gordon model|
|Autori:||Delfino, Gesualdo; Mussardo, Giuseppe|
|Data di pubblicazione:||1998|
|Digital Object Identifier (DOI):||10.1016/S0550-3213(98)00063-7|
|Appare nelle tipologie:||1.1 Journal article|