Description
Generically isolated quantum many-body systems reach a thermal equilib-
rium state upon unitary time evolution, which is explained by the Eigenstate
thermalization hypothesis. But, when disorder is added to these systems, the
dynamics becomes extremely slow. These systems are believed to evade ther-
malization even after very long time evolution. Our work sheds light on the slow
dynamics of these systems from a very different perspective, namely the internal
clock perspective. Considering the entanglement entropy as an internal clock,
we get an idea about the fate of these disordered systems (simulation done for
an XXZ chain) which can not be predicted from the real time simulation. We
extend this idea in a disordered floquet model where we study the relaxation
dynamics of local (inverse-) temperature. The broad distribution of relaxation
time of the local (inverse-) temperature even in the ergodic regime, suggests
us a striking similarity of this system with classical glasses which also show an
inhomogeneous relaxation dynamics. However, a unified perspective emerges
when considering the system’s diagonal entropy as an internal clock, revealing
an underlying homogeneity in the temperature dynamics for a broad range of
disorder strengths.
References
1) Internal clock of many-body delocalization, Phys. Rev. B 108, 134204, Ferdinand Evers, Ishita Modak, and Soumya Bera. https://journals.aps.org/prb/abstract/10.1103/PhysRevB.108.134204
2) Inhomogeneous Floquet thermalization, arXiv:2403.08369, Soumya Bera, Ishita Modak, Roderich Moessner. https://arxiv.org/abs/2403.08369
