摘要:

We briefly review results from a detailed Monte Carlo study of the critical properties of the 2‐D XY model at full frustration in a square lattice. We have obtained the critical exponents of the model from explicit calculations of the thermodynamic and correlation functions for the spin and chiral degrees of freedom. We found that the critical exponents of the spin phase transition are &ngr;=0.3069 and &eegr;=0.1915, which are to be compared with the unfrustrated XY model exponents &ngr;=0.5 and &eegr;=0.25. We also found that the critical exponents of the chiral transition are &ngr;&khgr;=0.875, 2&bgr;=0.1936, 2&ggr;=1.82, and 2&ggr;′=1.025, which are different from those expected for the 2‐D Ising model. We conclude that these results indicate that the fully frustrated XY model is in a new universality class. We also mention a successful comparison of the results for the spin degrees of freedom to experimental results in frustrated Josephson junction arrays.

ISSN:0094-243X    

DOI:10.1063/1.48766

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The status of dislocation theories of melting (DTM) is assessed. The role of dislocations in two other structural transformations is also discussed, namely vacancy annealing kinetics and fracture, ductile versus brittle. In these three problems the observed and predicted behaviors are correlated with the properties of the dislocations.

ISSN:0094-243X    

DOI:10.1063/1.48767

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

An overview of recent work concerning tracer diffusion under steady shear flow is presented. The description is made from the exact Boltzmann equation for Maxwell molecules as well as from a kinetic model for general repulsive interactions. The effect of shear flow on tracer diffusion is analyzed in terms of the mass ratio, the force constant ratio, and the interaction parameter.

ISSN:0094-243X    

DOI:10.1063/1.48768

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

We examine the scaling properties of correlations in the extended capillary‐wave model [Physica A184, 367 (1992)]. The procedure developed previously by Weeks and collaborators to study interfacial correlations applies to the extended case and reproduces most of the earlier features. The extended model is consistent with the expression for the bending rigidity given by the fourth moment of the direct correlation function. The scaling properties differ from those of the ordinary model whend=3, for which we find that the correlations obey scaling on length scales less thanLc.

ISSN:0094-243X    

DOI:10.1063/1.48769

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Elements of knot theory and knot invariants and their connections with exactly solvable models in two dimensions in statistical mechanics are reviewed. It is shown that knot invariants can be generated from vertex models and spin models with two‐spin interactions. The role played by the Yang‐Baxter equation is elucidated. The recently obtained results on the generation of a new kind of invariant on the basis of the solvable chiral Potts model and the generalized Gaussian summation are also described.

ISSN:0094-243X    

DOI:10.1063/1.48770

出版商:AIP    

年代:1995

数据来源: AIP