ﻻ يوجد ملخص باللغة العربية
We study the three-dimensional U(1)+Higgs theory (Ginzburg-Landau model) as an effective theory for finite temperature phase transitions from the 1 K scale of superconductivity to the relativistic scales of scalar electrodynamics. The relations between the parameters of the physical theory and the parameters of the 3d effective theory are given. The 3d theory as such is studied with lattice Monte Carlo techniques. The phase diagram, the characteristics of the transition in the first order regime, and scalar and vector correlation lengths are determined. We find that even rather deep in the first order regime, the transition is weaker than indicated by 2-loop perturbation theory. Topological effects caused by the compact formulation are studied, and it is demonstrated that they vanish in the continuum limit. In particular, the photon mass (inverse correlation length) is observed to be zero within statistical errors in the symmetric phase, thus constituting an effective order parameter.
We use lattice Monte Carlo simulations to study non-perturbatively the tension, i.e. the free energy per unit length, of an infinitely long vortex in the three-dimensional U(1)+Higgs theory. This theory is the low-energy effective theory of high-temp
We discuss a phase diagram for a relativistic SU(2) x U_{S}(1) lattice gauge theory, with emphasis on the formation of a parity-invariant chiral condensate, in the case when the $U_{S}(1)$ field is infinitely coupled, and the SU(2) field is moved awa
We study the three-dimensional (3D) compact U(1) lattice gauge theory coupled with $N$-flavor Higgs fields by means of the Monte Carlo simulations. This model is relevant to multi-component superconductors, antiferromagnetic spin systems in easy plan
We present and discuss the results of a Monte-Carlo simulation of the phase transition in pure compact U(1) lattice gauge theory with Wilson action on a hypercubic lattice with periodic boundary conditions. The statistics are large enough to make a t
We describe how the strings, which are classical solutions of the continuum three-dimensional U(1)+Higgs theory, can be studied on the lattice. The effect of an external magnetic field is also discussed and the first results on the string free energy