A new way to deal with fermions in Monte Carlo simulations

An exact, nonlocal, finite step-size algorithm for Monte Carlo simulation of theories with dynamical fermions is proposed. The algorithm is based on obtaining the new configuration U' from the old one U by solving the equation $M(U') \eta = \omega M(U) \eta$, where $M$ is fermionic operator, $\eta$ is random Gaussian vector, and $\omega$ is random real number close to unity. This algorithm can be used for the acceleration of current simulations in theories with Grassmann variables. A first test was done for SU(3) QCD with purely fermionic term in the action.Comment: 8 pages, latex, one section added, references correcte

A test of a new simulation algorithm for dynamical quarks

Some results of test runs on a $6^3\times 12$ lattice with Wilson quarks and gauge group SU(2) for a previously proposed fermion algorithm by A. Slavnov are presented.Comment: 10 pages, 3 figure

Higher covariant derivative regularization revisited

The method of higher covariant derivative regularization of gauge theories is reviewed. The objections raised in the literature last years are discussed and the consistency of the method is proven. New approach to regularization of overlapping divergencies is developped.Comment: 14 pages, latex, 1 figur

A practical gauge invariant regularization of the SO(10) grand unified model

It is shown that a simple modification of the dimensional regularization allows to compute in a consistent and gauge invariant way any diagram with less than four loops in the SO(10) unified model. The method applies also to the Standard Model generated by the symmetry breaking $SO(10) \to SU(3)\times SU(2)\times U(1)$. A gauge invariant regularization for arbitrary diagram is also described.Comment: 10 pages, uses linedraw.st

Noisy Monte Carlo Algorithm

We present an exact Monte Carlo algorithm designed to sample theories where the energy is a sum of many couplings of decreasing strength. The algorithm avoids the computation of almost all non-leading terms. Its use is illustrated by simulating SU(2) lattice gauge theory with a 5-loop improved action. A new approach for dynamical fermion simulations is proposed.Comment: Lattice 2000 (Algorithms), latex, espcrc2.sty, 4 page

Calculation of Finite Size Effects on the Nucleon Mass in Unquenched QCD using Chiral Perturbation Theory

The finite size effects on nucleon masses are calculated in relativistic chiral perturbation theory. Results are compared with two-flavor lattice results.Comment: talk at Confinement03, 5 pages latex, 3 figures. Assignment of 2 data points to incorrect data sets in plot 1 and of 1 data point in plot 2 corrected. 1 fm lattice result updated. Conclusions unchange