{
  "id": "1408.7013",
  "version": "v1",
  "published": "2014-08-29T13:26:54.000Z",
  "updated": "2014-08-29T13:26:54.000Z",
  "title": "The quantum phase transition and correlations in the multi-spin-boson model",
  "authors": [
    "André Winter",
    "Heiko Rieger"
  ],
  "comment": "16 pages, 21 figures",
  "categories": [
    "cond-mat.stat-mech",
    "cond-mat.str-el"
  ],
  "abstract": "We consider multiple non-interacting quantum mechanical two-level systems coupled to a common bosonic bath and study its quantum phase transition with Monte Carlo simulations using a continuous imaginary time cluster algorithm. The common bath induces an effective ferromagnetic interaction between the otherwise independent two-level systems, which can be quantified by an effective interaction strength. For degenerate energy levels above a critical value of the bath coupling strength $\\alpha$ all two-level systems freeze into the same state and the critical value $\\alpha_c$ decreases asymptotically as $1/N$ with increasing $N$. For a finite number, $N$, of two-level systems the quantum phase transition (at zero temperature) is in the same universality class as the single spin-boson model, in the limit $N\\to\\infty$ the system shows mean-field critical behavior independent of the power of the spectral function of the bosonic bath. We also study the influence of a spatial separation of the spins in a bath of bosonic modes with linear dispersion relation on the location and characteristics of the phase transition as well as on correlations between the two-level systems.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-08-29T13:26:54.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "05.10.Ln",
      "05.30.Jp",
      "03.65.Yz",
      "75.40.Mg"
    ],
    "keywords": [
      "quantum phase transition",
      "imaginary time cluster algorithm",
      "multi-spin-boson model",
      "quantum mechanical two-level systems",
      "non-interacting quantum mechanical two-level"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1103/PhysRevB.90.224401",
      "journal": "Physical Review B",
      "year": 2014,
      "month": "Dec",
      "volume": 90,
      "number": 22,
      "pages": 224401
    },
    "note": {
      "typesetting": "TeX",
      "pages": 16,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2014PhRvB..90v4401W"
    }
  }
}