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Title: Scrambling and thermalization in a diffusive quantum many-body system

Out-of-time ordered (OTO) correlation functions describe scrambling of information in correlated quantum matter. They are of particular interest in incoherent quantum systems lacking well defined quasi-particles. Thus far, it is largely elusive how OTO correlators spread in incoherent systems with diffusive transport governed by a few globally conserved quantities. Here, we study the dynamical response of such a system using high-performance matrix-product-operator techniques. Specifically, we consider the non-integrable, one-dimensional Bose–Hubbard model in the incoherent high-temperature regime. Our system exhibits diffusive dynamics in time-ordered correlators of globally conserved quantities, whereas OTO correlators display a ballistic, light-cone spreading of quantum information. The slowest process in the global thermalization of the system is thus diffusive, yet information spreading is not inhibited by such slow dynamics. We furthermore develop an experimentally feasible protocol to overcome some challenges faced by existing proposals and to probe time-ordered and OTO correlation functions. As a result, our study opens new avenues for both the theoretical and experimental exploration of thermalization and information scrambling dynamics.
Authors:
 [1] ; ORCiD logo [2] ;  [3] ;  [4]
  1. Technical Univ. of Munich, Garching (Germany); Harvard Univ., Cambridge, MA (United States)
  2. SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States)
  3. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  4. Technical Univ. of Munich, Garching (Germany)
Publication Date:
Grant/Contract Number:
AC02-76SF00515; KN 1254/1-1; 291763
Type:
Accepted Manuscript
Journal Name:
New Journal of Physics
Additional Journal Information:
Journal Volume: 19; Journal Issue: 6; Journal ID: ISSN 1367-2630
Publisher:
IOP Publishing
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; scrambling of quantum information; out-of-time ordered correlation functions; incoherent transport; many-body interferometry
OSTI Identifier:
1369417

Bohrdt, A., Mendl, C. B., Endres, M., and Knap, M.. Scrambling and thermalization in a diffusive quantum many-body system. United States: N. p., Web. doi:10.1088/1367-2630/aa719b.
Bohrdt, A., Mendl, C. B., Endres, M., & Knap, M.. Scrambling and thermalization in a diffusive quantum many-body system. United States. doi:10.1088/1367-2630/aa719b.
Bohrdt, A., Mendl, C. B., Endres, M., and Knap, M.. 2017. "Scrambling and thermalization in a diffusive quantum many-body system". United States. doi:10.1088/1367-2630/aa719b. https://www.osti.gov/servlets/purl/1369417.
@article{osti_1369417,
title = {Scrambling and thermalization in a diffusive quantum many-body system},
author = {Bohrdt, A. and Mendl, C. B. and Endres, M. and Knap, M.},
abstractNote = {Out-of-time ordered (OTO) correlation functions describe scrambling of information in correlated quantum matter. They are of particular interest in incoherent quantum systems lacking well defined quasi-particles. Thus far, it is largely elusive how OTO correlators spread in incoherent systems with diffusive transport governed by a few globally conserved quantities. Here, we study the dynamical response of such a system using high-performance matrix-product-operator techniques. Specifically, we consider the non-integrable, one-dimensional Bose–Hubbard model in the incoherent high-temperature regime. Our system exhibits diffusive dynamics in time-ordered correlators of globally conserved quantities, whereas OTO correlators display a ballistic, light-cone spreading of quantum information. The slowest process in the global thermalization of the system is thus diffusive, yet information spreading is not inhibited by such slow dynamics. We furthermore develop an experimentally feasible protocol to overcome some challenges faced by existing proposals and to probe time-ordered and OTO correlation functions. As a result, our study opens new avenues for both the theoretical and experimental exploration of thermalization and information scrambling dynamics.},
doi = {10.1088/1367-2630/aa719b},
journal = {New Journal of Physics},
number = 6,
volume = 19,
place = {United States},
year = {2017},
month = {6}
}