Physical review. B, Condensed matter

Phase diagram for the infinite-range transverse Ising spin-glass model

Terufumi Yokota

Published Nov 1, 1989• 16 citations

Abstract

We obtain the phase diagram for the infinite-range transverse Ising spin-glass model by the pair approximation. The transition temperature increases slightly for small transverse field \ensuremath{\Gamma} because the quantum fluctuation suppresses the reaction field. For \ensuremath{\Gamma}/J\ifmmode \tilde{}\else \~{}\fi{}>1+\ensuremath{\surd}3/8, the system is always paramagnetic.

DOI: 10.1103/physrevb.40.9321

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Physical review. B, Condensed matter

Phase diagram for the infinite-range transverse Ising spin-glass model

Terufumi Yokota

Published Nov 1, 1989• 16 citations

Publisher

Abstract

We obtain the phase diagram for the infinite-range transverse Ising spin-glass model by the pair approximation. The transition temperature increases slightly for small transverse field \ensuremath{\Gamma} because the quantum fluctuation suppresses the reaction field. For \ensuremath{\Gamma}/J\ifmmode \tilde{}\else ~{}\fi{}>1+\ensuremath{\surd}3/8, the system is always paramagnetic.

DOI: 10.1103/physrevb.40.9321

Related papers

Ising spin glass in a transverse magnetic field

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The infinite-range Ising spin-glass in the presence of a transverse field is studied by Monte Carlo simulations. The overlap probability distribution P ( q ) is defined and calculated for the present quantum case. The P ( q ) in the spin-glass phase has a long tail extended down to q = 0 qualitatively similar to the classical Sherrington-Kirkpatrick model. The phase boundary of the glass transition temperature vs. the transverse field is obtained. Our results for the phase diagram agree with our recent replica symmetry-breaking solution but disagree with the results of Yokata and of Ray et al.The infinite-range Ising spin-glass in the presence of a transverse field is studied by Monte Carlo simulations. The overlap probability distribution P ( q ) is defined and calculated for the present quantum case. The P ( q ) in the spin-glass phase has a long tail extended down to q = 0 qualitatively similar to the classical Sherrington-Kirkpatrick model. The phase boundary of the glass transition temperature vs. the transverse field is obtained. Our results for the phase diagram agree with our recent replica symmetry-breaking solution but disagree with the results of Yokata and of Ray et al.

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Phase diagrams of quantum spin glass models

Ferenc Pázmándi, Zbigniew Domański

Journal of Physics Condensed MatterMar 1, 19936 citations

{\mathit{T}}_{\mathit{c}}

vs transverse field \ensuremath{\Gamma}) we obtain shows a finite slope near T=0, in contrast with the infinite slope for the pure case. Our results compare very well with the experimental data recently obtained for the dipolar Ising spin glass

{\mathrm{LiHo}}_{0.167}

{\mathrm{Y}}_{0.833}

{\mathrm{F}}_{4}

, in a transverse field. This indicates that this system is more appropriately described by a model with short-range interactions than by an equivalent Sherrington-Kirkpatrick model in a transverse field.

{T}_{c}

are obtained including the case

{T}_{c}

\ensuremath{\rightarrow}0.

{\mathit{T}}_{\mathit{c}}

\ensuremath{\sim}exp[-

{\mathit{H}}^{2}

/(2

{\mathit{J}}^{2}

{\mathit{S}}^{2}

)], as compared with

{\mathit{T}}_{\mathit{c}}

\ensuremath{\sim}exp{-

{\mathit{H}}^{2}

/[2

{\mathit{J}}^{2}

S(S+1)]} for classical spins of magnitude \ensuremath{\surd}S(S+1) . In the case of QXYSG in a transverse field (\ensuremath{\Gamma}), the phase boundary terminates at \ensuremath{\Gamma}/J=2 for T=0.