Journal of High Energy Physics (Aug 2019)
Boundary entropy of integrable perturbed SU (2) k WZNW
Abstract
Abstract We apply the recently developped analytical methods for computing the boundary entropy, or the g-function, in integrable theories with non-diagonal scattering. We consider the particular case of the current-perturbed SU (2) k WZNW model with boundary and compute the boundary entropy for a specific boundary condition. The main problem we encounter is that in case of non-diagonal scattering the boundary entropy is infinite. We show that this infinity can be cured by a subtraction. The difference of the boundary entropies in the UV and in the IR limits is finite, and matches the known g-functions for the unperturbed SU (2) k WZNW model for even values of the level.
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