{
  "id": "0805.2339",
  "version": "v2",
  "published": "2008-05-15T15:46:49.000Z",
  "updated": "2009-04-17T08:23:58.000Z",
  "title": "A possible mechanism of concurring diagonal and off-diagonal long-range order for soft interactions",
  "authors": [
    "Andras Suto"
  ],
  "comment": "published version",
  "journal": "J. Math. Phys. 50, 032107 (2009)",
  "categories": [
    "cond-mat.stat-mech",
    "cond-mat.supr-con"
  ],
  "abstract": "This paper is a contribution to the theory of coherent crystals. We present arguments claiming that negative minima in the Fourier transform of a soft pair interaction may give rise to the coexistence of diagonal and off-diagonal long-range order at high densities, and that this coexistence may be detectable due to a periodicity seen on the off-diagonal part of the one-body reduced density matrix, without breaking translation invariance. As an illustration, we study the ground state of a homogenous system of bosons in continuous space, from the interaction retaining only the Fourier modes $v(\\k)$ belonging to a single nonzero wave number $|\\k|=q$. The result is a mean-field model. We prove that for $v(\\k)>0$ the ground state is asymptotically fully Bose-condensed, while for $v(\\k)<0$ at densities exceeding a multiple of $\\hbar^2 q^2/2m|v(\\k)|$ it exhibits both Bose-Einstein condensation and diagonal long-range order, and the latter can be seen on both the one- and the two-body density matrix.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2009-04-17T08:23:58.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "off-diagonal long-range order",
      "soft interactions",
      "concurring diagonal",
      "single nonzero wave number",
      "ground state"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "AIP",
      "journal": "J. Math. Phys."
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2008arXiv0805.2339S"
    }
  }
}