Zero-Temperature Responses of a 3D Spin Glass in a Magnetic Field

We probe the energy landscape of the 3D Edwards-Anderson spin glass in a magnetic field to test for a spin glass ordering. We find that the spin glass susceptibility is anomalously large on the lattice sizes we can reach. Our data suggest that a transition from the spin glass to the paramagnetic phase takes place at $B_c\approx 0.65$, though the possibility $B_c=0\mathrm{}$ cannot be excluded. We also discuss the question of the nature of the putative frozen phase.