Sergio Caracciolo

Dynamic critical exponent of some Monte Carlo algorithms for the self-avoiding walk

Discusses the dynamic critical behavior of some Monte Carlo algorithms for the self-avoiding walk (SAW). For algorithms with local N-conserving elementary moves, it is argued that the autocorrelation time behaves as tau approximately Np with p approximately=2+2 nu . For the BFACF dynamics (a grand canonical algorithm), Monte Carlo data is presented indicating that p=2.2+or-0.5 for two-dimensional non-reversal random walks and p=3.0+or-0.4 for two-dimensional SAW, values which are significantly less than 2+2 nu .

Two-loop critical mass for Wilson fermions

We have redone a recent two-loop computation of the critical mass for Wilson fermions in lattice QCD by evaluating Feynman integrals with the coordinate-space method. We present the results for different types of infrared regularization. We confirm both the previous numerical estimates and the power of the coordinate-space method whenever high accuracy is needed.

Universal distance ratios for two-dimensonal self-avoiding walks: corrected conformal-invariance predictions

The authors correct a combinatorial error in the Cardy-Saleur conformal-invariance prediction of a universal amplitude ratio for two-dimensional self-avoiding walks. They present high-precision Monte Carlo data that confirm the corrected prediction.

Monte Carlo test of a hyperscaling relation for the two-dimensional self-avoiding walk

The authors simulated self-avoiding walks on the square lattice with fixed endpoints by means of a dynamic Monte Carlo algorithm. From these data they obtain an evaluation of the effective coordination number mu and the critical exponents alpha and v. They can therefore test the hyperscaling relation 2- alpha =dv with a careful estimate of systematic and statistical errors.

Finite-Size Scaling in the Driven Lattice Gas

AbstractWe present a Monte Carlo study of the high-temperature phase of the two-dimensional driven lattice gas at infinite driving field. We define a finite-volume correlation length, verify that this definition has a good infinite-volume limit independent of the lattice geometry, and study its finite-size-scaling behavior. The results for the correlation length are in good agreement with the predictions based on the field theory proposed by Janssen, Schmittmann, Leung, and Cardy. The theoretical predictions for the susceptibility and the magnetization are also well verified. We show that the transverse Binder parameter vanishes at the critical point in all dimensions n

NONPERTURBATIVE LATTICE GRAVITY

d geqslant 2

The restoration of poincaré invariance and the energy momentum tensor in lattice gauge theories

n and discuss how such result should be expected in the theory of Janssen et al. in spite of the existence of a dangerously irrelevant operator. Our results confirm the Gaussian nature of the transverse excitations.

FROM LATTICE GAUGE THEORY TOWARDS GRAVITY

We define a transverse correlation length suitable to discuss the finite-size scaling behaviour of an out-of-equilibrium lattice gas, whose correlation functions decay algebraically with the distance. By numerical simulations we verify that this definition has a good infinite-volume limit independent of the lattice geometry. We study the transverse fluctuations as they can select the correct field-theoretical description. By means of a careful finite-size scaling analysis, without tunable parameters, we show that they are Gaussian, in agreement with the predictions of the field theory proposed by Janssen, Schmittmann, Leung and Cardy.