Entanglement of the 3-state Potts model via form factor bootstrap: total and symmetry resolved entropies
Luca Capizzi, Dávid X. Horváth, Pasquale Calabrese, Olalla A. Castro-Alvaredo
Abstract
A bstract In this paper, we apply the form factor bootstrap approach to branch point twist fields in the q -state Potts model for q ≤ 3. For q = 3 this is an integrable interacting quantum field theory with an internal discrete ℤ 3 symmetry and therefore provides an ideal starting point for the investigation of the symmetry resolved entanglement entropies. However, more generally, for q ≤ 3 the standard Rényi and entanglement entropies are also accessible through the bootstrap programme. In our work we present form factor solutions both for the standard branch point twist field with q ≤ 3 and for the composite (or symmetry resolved) branch point twist field with q = 3. In both cases, the form factor equations are solved for two particles and the solutions are carefully checked via the ∆-sum rule. Using our analytic predictions, we compute the leading finite-size corrections to the entanglement entropy and entanglement equipartition for a single interval in the ground state.