Self-averaging and criticality: A comparative study in 2d random bond spin models

N G Fytas; A Malakis

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arXiv · 0810.5438

Self-averaging and criticality: A comparative study in 2d random bond spin models

N G Fytas·A Malakis

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Abstract

We investigate and contrast, via the Wang-Landau (WL) algorithm, the effects of quenched bond randomness on the self-averaging properties of two Ising spin models in 2d. The random bond version of the superantiferromagnetic (SAF) square model with nearest- and next-nearest-neighbor competing interactions and the corresponding version of the simple ferromagnetic Ising model are studied. We find that, the random bond SAF model shows a strong violation of self-averaging, much stronger than that observed in the case of the random bond Ising model. Our analysis of the asymptotic scaling behavior of the variance of the distribution of the sample-dependent pseudocritical temperatures is found to be consistent with the renormalization group prediction of Aharony and Harris. Using this alternative approach, we find estimates of the correlation length exponent $ν$ in agreement with results obtained from the usual finite-size scaling (FSS) methodology.

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N G Fytas, A Malakis. 2008-10-30. Self-averaging and criticality: A comparative study in 2d random bond spin models. https://arxiv.org/abs/0810.5438

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