Using exact diagonalization techniques we study the dynamical response of the anisotropic disordered Heisenberg model for systems of S=1/2 spins with infinite range random exchange interactions at temperature T=0. The model can be considered as a generalization, to the quantum case, of the well known Sherrington-Kirkpatrick classical spin-glass model. We also compute and study the behavior of the Edwards Anderson order parameter and energy per spin as the anisotropy evolves from the Ising to the Heisenberg limits.Using exact diagonalization techniques we study the dynamical response of the anisotropic disordered Heisenberg model for systems of S=1/2 spins with infinite range random exchange interactions at temperature T=0. The model can be considered as a generalization, to the quantum case, of the well known Sherrington-Kirkpatrick classical spin-glass model. We also compute and study the behavior of the Edwards Anderson order parameter and energy per spin as the anisotropy evolves from the Ising to the Heisenberg limits.

arXiv:cond-mat/0412632Dec 22, 20040 citations

Random quantum magnets with broad disorder distribution

Dragi Karevski, Yu‐Cheng Lin, Heiko Rieger +2 more

arXiv:cond-mat/0009144The European Physical Journal BMar 1, 200153 citations

Magnetization plateaux in one-dimensional random quantum magnets

Kazuo Hida

Physica B Condensed MatterFeb 17, 20031 citation

First-order quantum phase transition in an anisotropic Ising model with infinite-range random interaction

J. Roberto Viana, Angsula Ghosh, J. Ricardo de Sousa

The phase diagram of the spin 1 quantum van Hemmen spin glass model with biaxial crystal-field anisotropy and a transverse magnetic field is studied. We investigate the effects of the two transverse crystal-field parameters ( ${D}_{x}$ and ${D}_{y}$ ) and transverse field $(\ensuremath{\Omega})$ on the phase diagrams in the $T\ensuremath{-}{D}_{x}$ plane for various values of ${D}_{y}$ and $\ensuremath{\Omega}$. Tricritical and reentrant behavior can be seen for appropriate ranges of these parameters.The phase diagram of the spin 1 quantum van Hemmen spin glass model with biaxial crystal-field anisotropy and a transverse magnetic field is studied. We investigate the effects of the two transverse crystal-field parameters (${D}_{x}$ and ${D}_{y}$) and transverse field $(\ensuremath{\Omega})$ on the phase diagrams in the $T\ensuremath{-}{D}_{x}$ plane for various values of ${D}_{y}$ and $\ensuremath{\Omega}$. Tricritical and reentrant behavior can be seen for appropriate ranges of these parameters.

Physical Review BJan 23, 20082 citations

Superconducting glass properties in the random infinite-range interaction Hubbard model: stability analysis and phase diagrams

T. K. Kopeć, P. Wróbel

The extended Hubbard model with on-site attraction and random infinite-range inter-site Coulomb interaction is studied for arbitrary band filling. In the strong-coupling limit the problem is mapped onto a system of hard-core bosons (local electron pairs) on a lattice described by the anisotropic pseudo-spin model with infinite-range random interactions-in close analogy to the standard Sherrington-Kirkpatrick spin-glass approach. With the use of thermofield dynamics as a substitute for the 'n-replica trick', and a one-loop approximation for the dynamic self-interaction, the stability of the mean-field-type solution with respect to the action of fluctuations is investigated in the parameter space including the temperature, degree of disorder and band-filling parameter.The extended Hubbard model with on-site attraction and random infinite-range inter-site Coulomb interaction is studied for arbitrary band filling. In the strong-coupling limit the problem is mapped onto a system of hard-core bosons (local electron pairs) on a lattice described by the anisotropic pseudo-spin model with infinite-range random interactions-in close analogy to the standard Sherrington-Kirkpatrick spin-glass approach. With the use of thermofield dynamics as a substitute for the 'n-replica trick', and a one-loop approximation for the dynamic self-interaction, the stability of the mean-field-type solution with respect to the action of fluctuations is investigated in the parameter space including the temperature, degree of disorder and band-filling parameter.

Journal of Physics Condensed MatterSep 10, 19902 citations

{D}_{x}

and

{D}_{y}

) and transverse field $(\ensuremath{\Omega})$ on the phase diagrams in the $T\ensuremath{-}{D}_{x}$ plane for various values of

{D}_{y}

and $\ensuremath{\Omega}$. Tricritical and reentrant behavior can be seen for appropriate ranges of these parameters.