Wednesday, June 20, 2012

1206.4270 (Jack Raymond et al.)

Next nearest neighbor Ising models on random graphs    [PDF]

Jack Raymond, K. Y. Michael Wong
This paper develops results for the next nearest neighbor Ising model on random graphs. We demonstrate ensembles of random graphs, including regular connectivity graphs, that have a periodic variation of free energy, with either the ratio of nearest to next nearest couplings, or the mean number of nearest neighbors. When the coupling ratio is integer paramagnetic phases can be found at zero temperature. This is shown to be related to the locked or unlocked nature of the interactions. For anti-ferromagnetic couplings, spin glass phases are demonstrated at low temperature. The interaction structure is formulated as a factor graph, the solution on a tree is developed. The replica symmetric and energetic one-step replica symmetry breaking solution is developed using the cavity method. We calculate within these frameworks the phase diagram and demonstrate the existence of dynamical transitions at zero temperature for cases of anti-ferromagnetic coupling on regular and inhomogeneous random graphs.
View original: http://arxiv.org/abs/1206.4270

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