Ising model

About: Ising model is a research topic. Over the lifetime, 25508 publications have been published within this topic receiving 555000 citations.

Bose condensation in quasi-one-dimensional antiferromagnets in strong fields.

Abstract: Recent experiments show that axially symmetric integer-spin antiferromagnetic chains undergo a phase transition at a critical applied magnetic field It was argued, using Landau-Ginzburg theory, that this is one-dimensional Bose condensation The theory is further analyzed at the mean-field and Gaussian level Then some exact results concerning the critical behavior are determined using known results on one-dimensional Bose fluids These are shown to be consistent with recent numerical simulations on spin chains Breaking of axial symmetry produces crossover to a two-dimensional Ising transition

Random-field instability of the ferromagnetic state

Abstract: We consider an Ising model with infinite-ranged interaction with statistically independent site fields with Gaussian distribution. The model is solved exactly and exhibits both an independent spin phase and a ferromagnetic phase, separated by a line of second-order phase transitions. We also establish that the replica technique yields exact results in the present model but not in the related random exchange system.

Field Theory: A Path Integral Approach

Abstract: Path Integrals and Quantum Mechanics Harmonic Oscillator Generating Functional Path Integrals for Fermions Supersymmetry Semi-Classical Methods Path Integral for the Double Well Path Integral for Relativistic Theories Effective Action Invariances and Their Consequences Gauge Theories Anomalies Systems at Finite Temperature Ising Model.

Global phase diagram for a three-component model

Abstract: The global phase diagram in a five-dimensional parameter space is described for a model which can be thought of as the "regular-solution" model of a ternary mixture or the mean-field approximation to a spin-1 Ising ferromagnet with a general nearest-neighbor interaction (the Blume-Capel model). The model possesses three fourth-order critical points (known from previous work) which are connected to a total of nine lines of tricritical points. Four manifolds of four-phase coexistence occur along with three manifolds of double critical points and six manifolds of critical double-end points. The locations of all significant features of the phase diagram are described qualitatively, and quantitative results are provided for some of the manifolds of lower dimension. Computational procedures are described which permit a detailed exploration of any portion of the phase diagram which may be of interest.

Dynamics of spreading phenomena in two-dimensional Ising models

Abstract: We consider the time evolution of two Ising systems that differ at time t=0 in the orientation of only one spin. The detailed time development is calculated from two algorithms: (i) Glauber dynamics and (ii) Q2R dynamics (a deterministic cellular automaton). We find that for both algorithms spreading of ``damaged regions'' is greatly hindered below a threshold temperature ${\mathrm{T}}_{\mathrm{s}}$ (or energy), which agrees numerically with the Curie point. For Glauber dynamics ${\mathrm{T}}_{\mathrm{s}}$ is found to be a sharp phase transition point; for Q2R dynamics we find a kinetic slowing down which is reminiscent of a (spin-) glass transition.