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Dynamics and transport in random quantum systems governed by strong-randomness fixed points

Motrunich, Olexei and Damle, Kedar and Huse, David A. (2001) Dynamics and transport in random quantum systems governed by strong-randomness fixed points. Physical Review B, 63 (13). Art. No. 134424. ISSN 0163-1829. https://resolver.caltech.edu/CaltechAUTHORS:MOTprb01a

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Abstract

We present results on the low-frequency dynamical and transport properties of random quantum systems whose low temperature (T), low-energy behavior is controlled by strong-disorder fixed points. We obtain the momentum- and frequency-dependent dynamic structure factor in the random singlet (RS) phases of both spin-1/2 and spin-1 random antiferromagnetic chains, as well as in the random dimer and Ising antiferromagnetic phases of spin-1/2 random antiferromagnetic chains. We show that the RS phases are unusual “spin metals” with divergent low-frequency spin conductivity at T=0, and we also follow the conductivity through “metal-insulator” transitions tuned by the strength of dimerization or Ising anisotropy in the spin-1/2 case, and by the strength of disorder in the spin-1 case. We work out the average spin and energy autocorrelations in the one-dimensional random transverse-field Ising model in the vicinity of its quantum critical point. All of the above calculations are valid in the frequency-dominated regime ω≳T, and rely on previously available renormalization group schemes that describe these systems in terms of the properties of certain strong-disorder fixed-point theories. In addition, we obtain some information about the behavior of the dynamic structure factor and dynamical conductivity in the opposite “hydrodynamic” regime ω<T for the special case of spin-1/2 chains close to the planar limit (the quantum x-y model) by analyzing the corresponding quantities in an equivalent model of spinless fermions with weak repulsive interactions and particle-hole symmetric disorder.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1103/PhysRevB.63.134424["eprint_fieldopt_related_url_type_DOI" not defined]UNSPECIFIED
ORCID:
AuthorORCID
Motrunich, Olexei0000-0001-8031-0022
Additional Information:© 2001 The American Physical Society Received 31 May 2000; revised 24 August 2000; published 13 March 2001 We thank P.W. Anderson, R.N. Bhatt, D. Dhar, D.S. Fisher, F.D.M. Haldane, M. Hastings, A. Millis, A. Madhav, R. Moessner, S. Sachdev, T. Senthil, S.L. Sondhi, and A. Vishwanath for useful discussions. This work was supported by NSF Grant Nos. DMR-9809483 and DMR-9802468.
Funders:
Funding AgencyGrant Number
NSFDMR-9809483
UNSPECIFIEDDMR-9802468
Issue or Number:13
Record Number:CaltechAUTHORS:MOTprb01a
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:MOTprb01a
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7136
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:09 Jan 2007
Last Modified:02 Oct 2019 23:39

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