S. Vinti

Rough interfaces beyond the Gaussian approximation

We compare predictions of the Capillary Wave Model with Monte Carlo results for the energy gap and the interface energy of the 3D Ising model in the scaling region. Our study reveals that the finite size effects of these quantities are well described by the Capillary Wave Model, expanded to two-loop order (one order beyond the Gaussian approximation).

On the behaviour of spatial Wilson loops in the high-temperature phase of LGT

Abstract The behaviour of the space-like string tension in the high temperature phase is studied. Data obtained in the Z 2 gauge model in (2+1) dimensions are compared with predictions of a simple model of a fluctuating flux tube with finite thickness. It is shown that in the high-temperature phase contributions coming from the fluctuations of the flux tube vanish. As a consequence we also show that in (2+1)-dimensional gauge theories the thickness of the flux tube coincides with the inverse of the deconfinement temperature.

Universal amplitude ratios in the 2D four-state Potts model

Abstract We present a Monte Carlo study of various universal amplitude ratios of the two-dimensional q =4 Potts model. We simulated the model close to criticality in both phases taking care to keep the systematic errors, due to finite size effects and logarithmic corrections in the scaling functions, under control. Our results are compatible with those recently obtained using the form-factor approach and with the existing low temperature series for the model.

Capillary wave approach to order-order fluid interfaces in the 3D three-state Potts model

The physics of fluid interfaces between domains of different magnetization in the ordered phase of the 3D three-state Potts model is studied by means of a Monte Carlo simulation. It is shown the finite-size effects in the interface free energy are well described by the capillary wave model at two loop order, supporting the idea of the universality of this description of fluid interfaces in 3D statistical models.

Nature of the vacuum inside the color flux tube

The interior of the color flux tube joining a quark pair can be probed by evaluating the correlator of pair of Polyakov loops in a vacuum modified by another Polyakov pair, in order to check the dual superconductivity conjecture, which predicts a deconfined, hot core. We also point out that at the critical point of any 3D gauge theories with a continuous deconfining transition the Svetitsky-Yaffe conjecture provides us with an analytic expression of the Polyakov correlator as a function of the location of the probe inside the flux tube. Both these predictions are compared with numerical results in 3D Z2 gauge model, finding complete agreement.

The 2D effective field theory of interfaces derived from 3D field theory

Abstract The one-loop determinant computed around the kink solution in the 3D φ4 theory, in cylindrical geometry, allows one to obtain the partition function of the interface separating coexisting phases. The quantum fluctuations of the interface around its equilibrium position are described by a c = 1 two-dimensional conformal field theory, namely a 2D free massless scalar field living on the interface. In this way the capillary wave model conjecture for the interface free energy in its gaussian approximation is proved.

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.

On the relation between the width of the flux tube and Tc−1 in lattice gauge theories☆

Within the framework of a quantum flux tube model for the interquark potential it is possible to predict that in (2+1) dimensions the space-like string tension must increase with the temperature in the deconfined phase and that the thickness of the flux tube must coincide with the inverse of the deconfinement temperature. Both these predictions are in good agreement with some recent numerical simuulations of SU(2) and Z2 gauge models.

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.

On the phase diagram of the discrete Z6 spin models

We point out some problems with the previously proposed phase diagram of the Z6 spin models. Consideration of the diagram near to the decoupling surface using both exact and approximate arguments suggests a modification which remedies these deficiencies. With the aid of a new parametrization of the phase space, we study the models numerically, with results which support our conjectures.We point out some problems with the previously-proposed phase diagram of the