Magnetization and entanglement after a geometric quench in the XXZ chain. (arXiv:1902.05834v1 [cond-mat.stat-mech])
We investigate the dynamics of the XXZ spin chain after a geometric quench,
which is realized by connecting two half-chains prepared in their ground states
with zero and maximum magnetizations, respectively. The profiles of
magnetization after the subsequent time evolution are studied numerically by
density-matrix renormalization group methods, and a comparison to the
predictions of generalized hydrodynamics yields a very good agreement. We also
calculate the profiles of entanglement entropy and propose an ansatz for the
noninteracting XX case, based on arguments from conformal field theory. In the
general interacting case, the propagation of the entropy front is studied
numerically both before and after the reflection from the chain boundaries.
Finally, our results for the magnetization fluctuations indicate a leading
order proportionality relation to the entanglement entropy.