Finite-volume spectra of the Lee-Yang model

Abstract

Abstract: We consider the non-unitary Lee-Yang minimal model ℳ2,5$$ \mathrm{\mathcal{M}}\left(2,\;5\right) $$ in three different finite geometries: (i) on the interval with integrable boundary conditions labelled by the Kac labels (r, s) = (1, 1), (1, 2), (ii) on the circle with periodic boundary conditions and (iii) on the periodic circle including an integrable purely transmitting defect. We apply φ1,3 integrable perturbations on the boundary and on the defect and describe the flow of the spectrum. Adding a Φ1,3 integrable perturbation to move off-criticality in the bulk, we determine the finite size spectrum of the massive scattering theory in the three geometries via Ther..