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Prethermalization and localization in quantum spin chains

P. Peng

Master’s thesis, Massachusetts Institute of Technology (2019)

Abstract

How can a quantum many-body system escape the fate of thermalization is of importance to both fundamental study of quantum statistical physics and applications in quantum devices. Here we develop novel experimental and computational tools to address this question. First, novel control techniques are introduced to investigate prethermalization, a process where a quantum system fails to thermalize on a practical timescale. Prethermalization is demonstrated by measuring out-of-time ordered (OTO) correlations in nuclear spin systems with magnetic resonance techniques. Hamiltonian engineering enables tuning the strength of spin-spin interactions and of a transverse magnetic field in a spin chain system, as well as to invert the Hamiltonian sign to reveal OTO correlations. The experiments reveal that at high fields an emergent conserved quantity arises due to prethermalization, and the OTO commutator involving such prethermal conserved quantity saturates after a short time.

BibTeX

@MastersThesis{Peng19t, author = {Peng, Pai}, school = {Massachusetts Institute of Technology}, title = {Prethermalization and localization in quantum spin chains}, year = {2019}, }