arXiv subjects

F. Ricci-Tersenghi

Publications and source records attributed to F. Ricci-Tersenghi.

57 records · Page 4Linked to original sources

arXiv1999

Absence of aging in the remanent magnetization in Migdal-Kadanoff spin glasses

We study the non-equilibrium behavior of three-dimensional spin glasses in the Migdal-Kadanoff approximation, that is on a hierarchical lattice. In this approximation the model has an unique ground state and equilibrium properties correctly described by the droplet model. Extensive numerical simulations show that this model lacks aging in the remanent magnetization as well as a maximum in the magnetic viscosity in disagreement with experiments as well as with numerical studies of the Edwards-Anderson model. This result strongly limits the validity of the droplet model (at least in its simplest form) as a good model for real spin glasses.

cond-mat.dis-nn↗

arXiv1999

Off-Equilibrium Dynamics at Very Low Temperatures in 3d Spin Glasses

We present a high statistic systematic study of the overlap correlation function well below the critical temperature in the three dimensional Gaussian spin glass. The off-equilibrium correlation function has been studied confirming the power law behavior for the dynamical correlation length. In particular we have computed the dynamical critical exponent $z$ in a wide range of temperatures, $0.35 \le T \le 0.9$, obtaining a dependence $z(T)=6.2/T$ in a very good agreement with recent experiments. Moreover, we report a study of the violation of the fluctuation-dissipation theorem for very low temperatures $T=0.5$ and $T=0.35$. All our numerical results avoid a droplet model interpretation even when $T$ is as low as $T=0.35$.

cond-mat.dis-nn↗

arXiv1998

Small Window Overlaps Are Effective Probes of Replica Symmetry Breaking in 3D Spin Glasses

We compute numerically small window overlaps in the three dimensional Edwards Anderson spin glass. We show that they behave in the way implied by the Replica Symmetry Breaking Ansatz, that they do not qualitatively differ from the full volume overlap and do not tend to a trivial function when increasing the lattice volume. On the contrary we show they are affected by small finite volume effects, and are interesting tools for the study of the features of the spin glass phase.

cond-mat.dis-nn↗