Multiple relaxation times in perturbed XXZ chain

Submission summary

 As Contributors: Jacek Herbrych Preprint link: scipost_202112_00036v2 Date submitted: 2022-05-21 19:56 Submitted by: Herbrych, Jacek Submitted to: SciPost Physics Academic field: Physics Specialties: Condensed Matter Physics - Theory Approaches: Theoretical, Computational

Abstract

We study numerically the relaxation of correlation functions in weakly perturbed integrable XXZ chain. While the decay of spin-current and energy-current correlations at zero magnetization are well described by single, but quite distinct, relaxation rates governed by the square of the perturbation strength $g$, the correlations at finite magnetization reveal multiple relaxation rates. The result can be understood in terms of decays of several quantities, conserved in the reference integrable system. On the other hand, the correlations of non-commuting quantities, being conserved at particular anisotropies $\Delta$, decay non-exponentially with characteristic time scale linear in $g$.

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