A conjectured scenario for order-parameter fluctuations in spin glasses

摘要: We study order-parameter fluctuations (OPF) in disordered systems by considering the behaviour of some recently introduced parameters G,Gc which have proven very useful locating phase transitions. prove that both G (for disconnected overlap disorder averages) and Gc connected take respective universal values (1/3) (13/31) T→0 limit for any finite volume provided ground state is unique there no gap ground-state local-field distributions, conditions are met generic spin-glass models with continuous couplings at zero coupling. This makes ideal to locate transitions much like Binder cumulant ordered systems. check our results exactly computing OPF a simple example uncoupled spins presence random fields one-dimensional Ising spin glass. At temperatures, we discuss under value may be recovered conjecturing different scenarios depending on whether or vanish infinite-volume limit. In particular, replica equivalence its natural consequence lim V→∞G(V,T) = when finite. As an model where does not give information about Sherrington-Kirkpatrick spherical performing numerical simulations small sizes. Again find compatible phase.