The infinite-range quantum transverse Ising spin-glass model

Terufumi Yokota

T. K. Kopeć, G. Büttner, Klaus D. Usadel

L. De Cesare, K. Lukierska‐Walasek, Ileana Rabuffo +1 more

Terufumi Yokota

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.

Ya. V. Fedorov, E. F. Shender

Katarzyna Walasek, K. Lukierska‐Walasek

The infinite-range quantum Ising spin-glass model in a transverse field \ensuremath{\Gamma} is studied within the cluster-expansion method formulated originally for spin systems by Morita and Tanaka. With use of the pair approximation, the mean-field equation and condition for critical values of ${\ensuremath{\Gamma}}_{c}$ and ${T}_{c}$ are obtained including the case ${T}_{c}$\ensuremath{\rightarrow}0.