Melting transition of an Ising glass driven by a magnetic field

The quantum critical behavior of the Ising glass in a magnetic field is investigated. We focus on the spin-glass-to-paramagnet transition of the transverse degrees of freedom in the presence of a finite longitudinal field. We use two complementary techniques, the Landau theory close to the T=0 transition and the exact diagonalization method for finite systems. This allows us to estimate the size of the critical region and characterize various crossover regimes. An unexpectedly small energy scale on the disordered side of the critical line is found, and its possible relevance to experiments on metallic glasses is briefly discussed.