Relaxation dynamics after a global quench in the massive XXZ chain

While there have been great advances in understanding the final equilibration of integrable systems after a quantum quench, relatively little is known about their precise relaxation towards the steady state. In this context, the XXZ chain provides a playground

for the investigation of interaction effects in out-of-equilibrium properties of quantum many-body

systems. We investigate the relaxation dynamics of equal-time correlations after a global quantum

quench of the anisotropy within the antiferromagnetic phase of the XXZ chain. In particular, we

consider the classical Neel state as the initial state. Using the exact solution of an effective free

model, numerical simulations and the quench action approach, we show that the late-time relaxation

of the oscillation amplitudes is characterized by a power-law decay with interaction-independent

exponents. Conversely, stationary values, amplitudes and oscillations frequencies depend on the

anisotropy. Overall, we show remarkable agreement in the results obtained from the distinct approaches.