Magnetic Tunnel Window's Imprint and Beyond

We report results from Monte Carlo simulations of systems of magnetic dipoles that relax through quantum tunneling, much as Fe_8 crystals at very low temperature.For short times, a hole develops in suitably defined magnetic field pseudo--distributions, which matches the shape of the tunnel window (TW). Much later, ordinary field distributions P(h) develop similar holes if thermal energies are not much larger than the TW's energy. Still later, below the long--range ordering (LRO) temperature, P(h) exhibits the signature of LRO.