F. Gliozzi

Width of long colour flux tubes in lattice gauge systems

Abstract In the confining phase of any gauge system the mean squared width of the colour flux tube joining a pair of quarks should grow logarithmically as a function of their distance, according to the effective string description of its infrared properties. New data on 3D 7L2 gauge theory, combined with high precision data on the interface physics of the 3D Ising model, nicely fit this behaviour over a range of more than two orders of magnitude.In the confining phase of any gauge system the mean squared width of the colour flux tube joining a pair of quarks should grow logarithmically as a function of their distance, according to the effective string description of its infrared properties. New data on 3D Z_2 gauge theory, combined with high precision data on the interface physics of the 3D Ising model fit nicely this behaviour over a range of more than two orders of magnitude.

Finite-size effects in the interface of the 3D Ising model

Abstract The interface between domains of opposite magnetization in the 3D Ising model near the critical temperature displays universal finite-size effects which can be described in terms of a gaussian model of capillary waves. It turns out that these finite-size corrections depend rather strongly on the shape of the lattice. This prediction, which has no adjustable parameters, is tested and accurately verified for various lattice shapes by means of numerical simulations with a cluster algorithm. This supports also a long-standing conjecture on the finite-size effects in Wilson loops of lattice gauge theories.

The effective string of 3D gauge systems at the deconfining transition

Abstract It is argued that the effective string of whatever 3D gauge system at the deconfining transition is universally described by the minimal N = 2 extended superconformal theory at c = 1. A universal value of the critical temperature is predicted.

Critical behavior of 3D SU(2) gauge theory at finite temperature: Exact results from universality

We show that universality arguments, namely the Svetitsky-Yaffe conjecture, allow one to obtain exact results on the critical behavior of 3D SU(2) gauge theory at the finite temperature deconfinement transition,through a mapping into the 2D Ising model. In particular, we consider the finite-size scaling behavior of the plaquette operator, which can be mapped into the energy operator of the 2D Ising model. We obtain exact predictions for the dependence of the plaquette expectation value on the size and shape of the lattice and we compare them to Monte Carlo results, finding complete agreement. We discuss the application of this method to the computation of more general correlators of the plaquette operator at criticality, and its relevance to the study of the color flux tube structure.

STRING CONTRIBUTIONS IN 3D Z2 AND Z5 GAUGE MODELS

We describe a high precision Monte Carlo test on Z2 and Z5 gauge models in 3D. Wilson loops of size 2≤R, T≤12 are measured and values of the string tension σ are extracted. These values fulfil asymptotic scaling if and only if the string contributions, namely the quantum fluctuations of the surfaces bordered by Wilson loops, are properly taken into account. As a byproduct of our analysis we find the signature of the finite thickness of these flux tubes.

Critical boundary conditions for the effective string

Abstract Gauge systems in the confining phase induce constraints at the boundaries of the effective string which rule out the ordinary bosonic string even with short distance modifications. Allowing topological excitations, corresponding to winding around the colour flux tube, produces at the quantum level a universal free fermion string with a boundary phase ν = 1 4 . This coincides with a model proposed some time ago in order to fit Monte Carlo data of 3D and 4D lattice gauge systems better. A universal value of the thickness of the colour flux tube is predicted.Gauge systems in the confining phase induce constraints at the boundaries of the effective string, which rule out the ordinary bosonic string even with short distance modifications. Allowing topological excitations, corresponding to winding around the colour flux tube, produces at the quantum level a universal free fermion string with a boundary phase nu=1/4. This coincides with a model proposed some time ago in order to fit Monte Carlo data of 3D and 4D Lattice gauge systems better. A universal value of the thickness of the colour flux tube is predicted.

No leftons for heterotic superstrings

Abstract We address the question whether the group-manifold reformulation of D =4 fermionic superstrings can be generalized through the use of the lefton-righton formalism. We show that in heterotic superstring models with world-sheet supersymmetry sitting in the left sector the cancellation of the Siegel anomaly forbids the presence of leftons and of non-moving bosons. Rightons are allowed and can replace some, but not all of the heterotic fermions. We also give the supersymmetric extension of the classical action for non-movers and we explain the origin of its peculiar structure within a first-order formulation.

THE EFFECTIVE STRING OF 3D Z2 GAUGE THEORY AS A c = 1 COMPACTIFIED CFT

We report on a high precision Monte Carlo test of the three-dimensional Ising gauge model at finite temperature. The string tension σ is extracted from the expectation values of correlations of Polyakov lines. Agreement with the string tension extracted from Wilson loops is found only if the quantum fluctuations of the flux tube are properly taken into account. The central charge of the underlying conformal field theory is c = 1.

Self-avoiding effective strings in lattice gauge theories☆

Abstract It is shown that the effective string recently introduced to describe the long distance dynamics of 3D gauge systems in the confining phase has an intriguing description in terms of models of 2D self-avoiding walks in the dense phase. The deconfinement point, where the effective string becomes N =2 supersymmetric, may then be interpreted as the tricritical Θ point where the polymer chain undergoes a collapse transition. As a consequence, a universal value of the deconfinement temperature is predicted.

(2, 2) VACUA OF THE HETEROTIC SUPERSTRING COMPACTIFIED ON SU(2)3 GROUPFOLDS

In this paper we classify the (2, 2) superstring vacua corresponding to non-linear σ-models on SU(2)3 groupfolds fermionized by 18 + 18 Majorana fermions. For the subclass of the completely bosonizable vacua, the generation number ½X is a multiple of 12 and the number of tangent-bundle deformations End(T) is a multiple of 4. The dimensions of the moduli spaces h1,1, h2, 1 are small odd numbers in the range 1 ÷ ~50. Very few of these vacua have the same Dolbeault cohomology as those described by minimal model tensor products, CICY, or Calabi-Yau threefolds in weighted P4. The vacua we classify are characterized by a rank 8 enhancement group and some of them can be viewed as N=2 truncations. We also discuss examples of vacua that are only partially bosonizable, showing that the class of vacua obtained by free fermion constructions is not fully contained in the class of vacua obtained by lattice constructions.