Low-frequency conductivity in many-body localized systems

Sarang Gopalakrishnan, Markus Müller, Vedika Khemani, Michael Knap, Eugene Demler, and David A. Huse
Phys. Rev. B 92, 104202 – Published 11 September 2015

Abstract

We argue that the ac conductivity σ(ω) in the many-body localized phase is a power law of frequency ω at low frequency: specifically, σ(ω)ωα with the exponent α approaching 1 at the phase transition to the thermal phase, and asymptoting to 2 deep in the localized phase. We identify two separate mechanisms giving rise to this power law: deep in the localized phase, the conductivity is dominated by rare resonant pairs of configurations; close to the transition, the dominant contributions are rare regions that are locally critical or in the thermal phase. We present numerical evidence supporting these claims, and discuss how these power laws can also be seen through polarization-decay measurements in ultracold atomic systems.

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  • Received 5 May 2015
  • Revised 22 August 2015

DOI:https://doi.org/10.1103/PhysRevB.92.104202

©2015 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Sarang Gopalakrishnan1, Markus Müller2, Vedika Khemani3,4, Michael Knap1,5, Eugene Demler1, and David A. Huse3

  • 1Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
  • 2The Abdus Salam International Center for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
  • 3Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
  • 4Max-Planck-Institut für Physik komplexer Systeme, 01187 Dresden, Germany
  • 5ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA

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Issue

Vol. 92, Iss. 10 — 1 September 2015

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