Boundary reflection matrices of massive $\phi_{1,3}$-perturbed unitary minimal models

Abstract

We propose explicit expressions for the boundary reflection matrices of the ${\cal A}_m+(r,s)$ series of massive scattering theories, obtained by perturbing the ${\cal A}_m$ unitary minimal models with $(r,s)$ boundary conditions with both bulk and boundary $\phi_{1,3}$ operators. We identify the vacua that live on the boundary with the allowed edges of the $(r,s)$ conformal boundary conditions of the $A_m$ Andrews-Baxter-Forrester model. The boundary reflection matrices are then ``direct sums'' of certain pairs of $A_{m-1}$ Behrend-Pearce solutions of the boundary Yang-Baxter equation and are consistent with the boundary bootstrap and the recently-introduced crossing, as well as the $Z_{2}$ (height-reversal), Kac table and non-invertible symmetries.