4 research outputs found
Quantum phase transition in spin glasses with multi-spin interactions
We examine the phase diagram of the -interaction spin glass model in a
transverse field. We consider a spherical version of the model and compare with
results obtained in the Ising case. The analysis of the spherical model, with
and without quantization, reveals a phase diagram very similar to that obtained
in the Ising case. In particular, using the static approximation, reentrance is
observed at low temperatures in both the quantum spherical and Ising models.
This is an artifact of the approximation and disappears when the imaginary time
dependence of the order parameter is taken into account. The resulting phase
diagram is checked by accurate numerical investigation of the phase boundaries.Comment: 20 Pages including 10 figures, Revte
Classical and Quantum Behavior in Mean-Field Glassy Systems
In this talk I review some recent developments which shed light on the main
connections between structural glasses and mean-field spin glass models with a
discontinuous transition. I also discuss the role of quantum fluctuations on
the dynamical instability found in mean-field spin glasses with a discontinuous
transition. In mean-field models with pairwise interactions in a transverse
field it is shown, in the framework of the static approximation, that such
instability is suppressed at zero temperature.Comment: 9 Pages (including 5 Figures), Revtex, Proceedings of the XIV Sitges
Conference, June 1996 (Barcelona) Spai
Quantum critical effects in mean-field glassy systems
We consider the effects of quantum fluctuations in mean-field quantum spin-glass models with pairwise interactions. We examine the nature of the quantum glass transition at zero temperature in a transverse field. In models (such as the random orthogonal model) where the classical phase transition is discontinuous an analysis using the static approximation reveals that the transition becomes continuous at zero temperature