Quick search Find article
Quick search
Find article

Site-disordered spin systems in the Gaussian variational approximation

David S Dean and David Lancaster

Show affiliations


We define a replica field theory describing finite dimensional site-disordered spin systems by introducing the notion of grand canonical disorder, where the number of spins in the system is random but quenched. A general analysis of this field theory is made using the Gaussian variational or Hartree - Fock method, and illustrated with several specific examples. Irrespective of the form of interaction between the spins this approximation predicts a spin-glass phase. We discuss the replica symmetric phase at length, explicitly identifying the correlator that diverges at the spin-glass transition. We also discuss the form of continuous replica symmetry breaking found just below the transition. Finally we show how an analysis of ferromagnetic ordering indicates a breakdown of the approximation.


PACS

05.50.+q Lattice theory and statistics (Ising, Potts, etc.)

05.70.Fh Phase transitions: general studies

75.50.Lk Spin glasses and other random magnets

MSC

60G15 Gaussian processes

82B44 Disordered systems (random Ising models, random Schrödinger operators, etc.)

82B26 Phase transitions (general)

82D40 Magnetic materials

82D30 Random media, disordered materials (including liquid crystals and spin glasses)

Subjects

Condensed matter: electrical, magnetic and optical

Statistical physics and nonlinear systems

Dates

Issue 1 (7 January 1997)

Received 10 June 1996, in final form 29 August 1996



  1. Site-disordered spin systems in the Gaussian variational approximation

    David S Dean and David Lancaster 1997 J. Phys. A: Math. Gen. 30 37

  2. GaAs membrane supported millimeter-wave receiver structures

    G Konstantinidis et al 2003 J. Micromech. Microeng. 13 353

  3. Dependence of deposition parameters and layer thickness on the characteristics of Nd-Fe-B thin films

    S Madeswaran et al 2009 J. Phys.: Conf. Ser. 191 012024

  4. Maximum permissible fluence

    T E Burlin and B M Wheatley 1980 Phys. Med. Biol. 25 745

  5. Non-contact AFM study of the oxidized surface of single-crystalline SrTiO3 with porphyrin-based molecules

    Shukichi Tanaka et al 2005 Nanotechnology 16 S107

  6. Confinement characteristics of high-energy ions produced by ICRF heating in the large helical device

    R Kumazawa et al 2003 Plasma Phys. Control. Fusion 45 1037

  7. LIGO: the Laser Interferometer Gravitational-Wave Observatory

    B P Abbott et al 2009 Rep. Prog. Phys. 72 076901

  8. Chern-Simons gravity and holographic anomalies

    Maximo Bañados et al JHEP05(2004)039

  9. Electrical properties of polyaniline nanofibre synthesized with biocatalyst

    Byoung-Kye Kim et al 2005 Nanotechnology 16 1177

  10. A model calculation for the α-α' phase transition in metal-hydrogen systems

    H Horner and H Wagner 1974 J. Phys. C: Solid State Phys. 7 3305

View by subject




Export








Please login to access our web services, or create an account if you don't yet have one.

You must have cookies enabled in your web browser to be able to login.

Username
Password

Forgotten your password? Get a new one here.