arXiv:cond-mat/0309576 · Journal of Physics A Mathematical and General
Parisi states in a Heisenberg spin-glass model in three dimensions
Fumitaka Matsubara, Takayuki Shirakura, Y Baba
Abstract
Having developed a hybrid genetic algorithm, we have studied low-lying excited states of the ± J Heisenberg model in two ( d = 2) and three ( d = 3) dimensions. We have found evidence of the occurrence of the Parisi states in d = 3 but not in d = 2. That is, in L d lattices, there exist metastable states with a finite excitation energy of Δ E ∼ O ( J ) for L → ∞, and energy barriers Δ W between the ground state and those metastable states are Δ W ∼ O ( JL θ ) with θ > 0 in d = 3 but with θ < 0 in d = 2. This finding favours the replica-symmetry-breaking or the trivial–nontrivial scenario of the SG phase over the droplet scenario.