Searcharxiv⌕ Search

arXiv subjects

J. L. Alonso

Publications and source records attributed to J. L. Alonso.

60 records · Page 4Linked to original sources
arXiv1995

A Monte Carlo study of O(3) antiferromagnetic models in three dimensions

We study three antiferromagnetic formulations of the O(3) spin model in three dimensions by means of Monte Carlo simulations: 1. a two parameter $σ$ model with nearest and next to nearest neighbors couplings in a cubic lattice; 2. a face centered cubic lattice with nearest neighbors interaction; 3. a cubic lattice with a set of fully frustrating couplings. We discuss in all cases the vacua properties and analyze the phase transitions. Using Finite Size Scaling analysis we conclude that all phase transitions found are of first order.

cond-mat↗
arXiv1995

On ferrimagnetic phases in chiral Yukawa models

We discuss the phase structure of chiral Yukawa models in the mean-field approximation. In particular, we examine under which conditions a ferrimagnetic phase appears, by calculating the slopes of possible second order phase transition lines near a critical point. Our results contrast with some statements which appeared in the literature recently.

hep-lat↗
arXiv1994

Roma versus Zaragoza

The Roma and Zaragoza actions for chiral fermions on the lattice are shown to be essentially equivalent. The auxiliary fermion fields in the Roma model can be integrated out, and the resulting action is a special case of the Zaragoza approach. We use this result to perform a mean-field study of the phase diagram of chiral Yukawa models in the Roma formulation.

hep-lat↗
arXiv1994

Phase Diagram of An SU(2)xSU(2) Scalar-Fermion Model with Massless Decoupled Doublers

We present the phase structure of the chiral SU(2)xSU(2) scalar-fermion model on the lattice using the Zaragoza proposal for chiral fermions. The numerical result agrees with an analytic study based on the use of weak and strong Yukawa coupling expansions combined with the mean field approach. The phase diagram consits of four phases: paramagnetic(PM), ferromagnetic(FM), antiferromagnetic(AFM) and ferrimagnetic (FI). The transition lines separating these four phases intersect at one quadruple point.

hep-lat↗
arXiv1992

Massless Decoupled Doublers: Chiral Yukawa Models and Chiral Gauge Theories

We present a new method for regularizing chiral theories on the lattice. The arbitrariness in the regularization is used in order to decouple massless replica fermions. A continuum limit with only one fermion is obtained in perturbation theory and a Golterman-Petcher like symmetry related to the decoupling of the replicas in the non-perturbative regime is identified. In the case of Chiral Gauge Theories gauge invariance is broken at the level of the regularization, so our approach shares many of the characteristics of the Rome approach.

hep-lat↗