Physical review. B, Condensed matter
Cluster-expansion method for the infinite-range quantum transverse Ising spin-glass model
Katarzyna Walasek, K. Lukierska‐Walasek
Abstract
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.