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 $\ensuremath{\chi}(T)$ and in the specific heat ${c}_{H}(T)$ at a characteristic temperature ${T}_{f}$ for finite spin $S$ and zero slope for $S\ensuremath{\rightarrow}\ensuremath{\infty}$. The specific heat is proportional to $T$ for $T\ensuremath{\rightarrow}0$, whereas it tends to the Boltzmann constant $k$ in the classical limit.