Emergence of a non-trivial fluctuating phase in the XY-rotors model on regular networks
Centre de Physique Théorique, CNRS - Aix-Marseille Université - Luminy, Case 907, F-13288 Marseille cedex 9, France, EU
Received: 28 September 2012
Accepted: 11 December 2012
We study an XY-rotor model on regular one-dimensional lattices by varying the number of neighbours. The parameter 2 ⩾ γ ⩾ 1 is defined. γ = 2 corresponds to mean field and γ = 1 to nearest-neighbours coupling. We find that for γ < 1.5 the system does not exhibit a phase transition, while for γ > 1.5 the mean-field second-order transition is recovered. For the critical value γ = γc = 1.5, the systems can be in a non-trivial fluctuating phase for which the magnetisation shows important fluctuations in a given temperature range, implying an infinite susceptibilty. For all values of γ the magnetisation is computed analytically in the low-temperatures range and the magnetised vs. non-magnetised states are recovered, confirming the critical value γc = 1.5.
PACS: 05.20.-y – Classical statistical mechanics / 05.45.-a – Nonlinear dynamics and chaos
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