Slowest local operators in quantum spin chains

Hyungwon Kim, Mari Carmen Bañuls, J. Ignacio Cirac, Matthew B. Hastings, David A. Huse

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

We numerically construct slowly relaxing local operators in a nonintegrable spin-1/2 chain. Restricting the support of the operator to M consecutive spins along the chain, we exhaustively search for the operator that minimizes the Frobenius norm of the commutator with the Hamiltonian. We first show that the Frobenius norm bounds the time scale of relaxation of the operator at high temperatures. We find operators with significantly slower relaxation than the slowest simple "hydrodynamic" mode due to energy diffusion. Then we examine some properties of the nontrivial slow operators. Using both exhaustive search and tensor network techniques, we find similar slowly relaxing operators for a Floquet spin chain; this system is hydrodynamically "trivial," with no conservation laws restricting their dynamics. We argue that such slow relaxation may be a generic feature following from locality and unitarity.

Original languageEnglish (US)
Article number012128
JournalPhysical Review E - Statistical, Nonlinear, and Soft Matter Physics
Volume92
Issue number1
DOIs
StatePublished - Jul 22 2015

All Science Journal Classification (ASJC) codes

  • Statistical and Nonlinear Physics
  • Statistics and Probability
  • Condensed Matter Physics

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