Entanglement of stationary states in the presence of unstable quasiparticles

• DOI: 10.1007/jhep04(2023)091
• Publication Date: 2023-04-21T09:08:33Z
• Authors: Dávid X. Horváth; Pasquale Calabrese; Olalla A. Castro-...
• Keywords: Stationary state

A bstract The effect of unstable quasiparticles in the out-of-equilibrium dynamics certain integrable systems has been subject several recent studies. In this paper we focus on stationary value entanglement entropy density, its growth rate, and related functions, after a quantum quench. We consider quenches, each which is characterised by corresponding squeezed coherent state. quench action approach, state amplitudes K ( θ ) become input data that fully characterise large-time state, thus also Yang-Yang entropy. find that, as function mass particle, rate global minimum signalling depletion accompanies slowdown stable at threshold for formation an excitation. observe separation scales governed interplay between particle parameter, separating non-interacting regime described free fermions from interacting where present. This leads to double-plateau structure many relative height plateaux ratio central charges UV fixed points associated with two regimes, full agreement conformal field theory predictions. properties other functions are studied detail, both parameter varying viceversa.