Please use this identifier to cite or link to this item: http://hdl.handle.net/2445/18840
 Title: Universality of fluctuation-dissipation ratios: The ferromagnetic model Author: Garriga A.Sollich PeterPagonabarraga Mora, IgnacioRitort Farran, Fèlix Keywords: Física matemàticaFísicaMathematical physicsPhysics Issue Date: 2005 Publisher: The American Physical Society Abstract: We calculate analytically the fluctuation-dissipation ratio (FDR) for Ising ferromagnets quenched to criticality, both for the long-range model and its short-range analogue in the limit of large dimension. Our exact solution shows that, for both models, $X^\infty=1/2$ if the system is unmagnetized while $X^\infty=4/5$ if the initial magnetization is non-zero. This indicates that two different classes of critical coarsening dynamics need to be distinguished depending on the initial conditions, each with its own nontrivial FDR. We also analyze the dependence of the FDR on whether local and global observables are used. These results clarify how a proper local FDR (and the corresponding effective temperature) should be defined in long-range models in order to avoid spurious inconsistencies and maintain the expected correspondence between local and global results; global observables turn out to be far more robust tools for detecting non-equilibrium FDRs. Note: Reproducció del document publicat a: http://dx.doi.org/10.1103/PhysRevE.72.056114 It is part of: Physical Review E, 2005, vol. 72, núm. 5, p. 056114-1-056114-13 Related resource: http://doi.org/10.1103/PhysRevE.72.056114 URI: http://hdl.handle.net/2445/18840 ISSN: 1063-651X Appears in Collections: Articles publicats en revistes (Física de la Matèria Condensada)

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