Static Properties of Spin Glasses

A recent classical theory for spin glasses of Edwards and Anderson is modified for the quantum mechanical case. One obtains a cusp in the susceptibility $\chi \mathrm{}\left(T\right)\mathrm{}$ and in the specific heat $c_H\mathrm{}\left(T\right)\mathrm{}$ at a characteristic temperature $T_f$ for finite spin $S$ and zero slope for $S\to \infty$. The specific heat is proportional to $T$ for $T\to 0$, whereas it tends to the Boltzmann constant $k$ in the classical limit.