Varying the Unruh temperature in integrable quantum field theories

Abstract

A computational scheme is developed to determine the response of a quantum field theory (QFT) with a factorized scattering operator under a variation of the Unruh temperature. To this end a new family of integrable systems is introduced, obtained by deforming such QFTs in a way that preserves the bootstrap S-matrix. The deformation parameter β plays the role of an inverse temperature for the thermal equilibrium states associated with the Rindler wedge, β = 2 π being the QFT value. The form factor approach provides an explicit computational scheme for the β ≠ 2 π systems, enforcing in particular a modification of the underlying kinematical arena. As examples deformed counterparts of the Ising model and the sinh-Gordon model are considered.