{
  "id": "1312.0515",
  "version": "v2",
  "published": "2013-12-02T16:49:36.000Z",
  "updated": "2014-09-02T21:51:04.000Z",
  "title": "Replica symmetry breaking in the Bose glass",
  "authors": [
    "S. J. Thomson",
    "F. Krüger"
  ],
  "comment": "6 pages, 3 figures, improved version with additional references",
  "categories": [
    "cond-mat.dis-nn"
  ],
  "abstract": "We investigate the nature of the Bose glass phase of the disordered Bose-Hubbard model in $d>2$ and demonstrate the existence of a glass-like replica symmetry breaking (RSB) order parameter in terms of particle number fluctuations. Starting from a strong-coupling expansion around the atomic limit, we study the instability of the Mott insulator towards the formation of a Bose glass. We add some infinitesimal RSB, following the Parisi hierarchical approach in the most general form, and observe its flow under the momentum-shell renormalization group scheme. We find a new fixed point with one-step RSB, corresponding to the transition between the Mott insulator and a Bose glass phase with hitherto unseen RSB. The susceptibility associated to infinitesimal RSB perturbation in the Mott insulator is found to diverge at the transition with an exponent of $\\gamma=1/d$. Our findings are consistent with the expectation of glassy behavior and the established breakdown of self-averaging. We discuss the possibility of measuring the glass-like order parameter in optical lattice experiments as well as in certain spin systems that are in the same universality class as the Bose-Hubbard model.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2013-12-02T16:49:36.000Z",
      "title": "The order parameter of the Bose glass",
      "abstract": "We investigate the nature of the Bose-glass phase of the disordered Bose-Hubbard model and demonstrate the existence of a glass-like replica symmetry breaking (RSB) order parameter in terms of particle number fluctuations. Starting from a strong-coupling expansion around the atomic limit, we study the instability of the Mott insulator towards the formation of a Bose glass. We add some infinitesimal RSB, following the Parisi hierarchical approach in the most general form, and observe its flow under the momentum-shell renormalization group scheme. We find a new fixed point with one-step RSB, corresponding to the transition between the Mott insulator and a Bose glass phase with hitherto unseen RSB. This finding is consistent with the expectation of glassy behavior and previous results showing the breakdown of self-averaging. We discuss the possibility of measuring the glass-like order parameter in optical lattice experiments.",
      "comment": "5 pages, 4 figures",
      "journal": null,
      "doi": null
    },
    {
      "version": "v2",
      "updated": "2014-09-02T21:51:04.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "order parameter",
      "momentum-shell renormalization group scheme",
      "mott insulator",
      "bose glass phase",
      "particle number fluctuations"
    ],
    "publication": {
      "doi": "10.1209/0295-5075/108/30002",
      "journal": "EPL (Europhysics Letters)",
      "year": 2014,
      "month": "Nov",
      "volume": 108,
      "number": 3,
      "pages": 30002
    },
    "note": {
      "typesetting": "TeX",
      "pages": 6,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2014EL....10830002T"
    }
  }
}