Dynamic scaling in diluted systems: Deactivation through thermal dilution - art. no. 056114

Activated scaling is confirmed to hold in transverse field-induced phase tr ansitions of randomly diluted Ising systems. Quantum Monte Carte calculatio ns have been made not just at the percolation threshold (p(c)) but also wel l below and above it. We follow the evolution of the activated scaling at z ero temperature in the phase transition from ferromagnetic to quantum Griff iths phase (p > p(c)) at the phase boundary (p = p(c)) and for transitions inside the nonferromagnetic quantum Griffiths phase (p < p(c)). A novel dea ctivation phenomenon inside the nonferromagnetic Griffiths-McCoy phase (p < p(c)) is observed using a thermal (in contrast to random) dilution of the system.