8 research outputs found
Spin-Glass Attractor on Tridimensional Hierarchical Lattices in the Presence of an External Magnetic Field
A nearest-neighbor-interaction Ising spin glass, in the presence of an
external magnetic field, is studied on different hierarchical lattices that
approach the cubic lattice. The magnetic field is considered as uniform, or
random (following either a bimodal or a Gaussian probability distribution). In
all cases, a spin-glass attractor is found, in the plane magnetic field versus
temperature, associated with a low-temperature phase. The physical consequences
of this attractor are discussed, in view of the present scenario of the
spin-glass problem.Comment: Accepted for publication in Physical Review
Multicritical Behavior in a Random-Field Ising Model under a Continuous-Field Probability Distribution
A random-field Ising model that is capable of exhibiting a rich variety of
multicritical phenomena, as well as a smearing of such behavior, is
investigated. The model consists of an infinite-range-interaction Ising
ferromagnet in the presence of a triple-Gaussian random magnetic field, which
is defined as a superposition of three Gaussian distributions with the same
width , centered at H=0 and , with probabilities and
, respectively. Such a distribution is very general and recovers as
limiting cases, the trimodal, bimodal, and Gaussian probability distributions.Comment: 25 pages, 21 figures, articl