Mass gap in the 2D O(3) non-linear sigma model with a theta=pi term
Statistical Mechanics
2008-11-26 v2 Other Condensed Matter
High Energy Physics - Lattice
Abstract
By analytic continuation to real theta of data obtained from numerical simulation at imaginary theta we study the Haldane conjecture and show that the O(3) non-linear sigma model with a theta term in 2 dimensions becomes massless at theta=3.10(5). A modified cluster algorithm has been introduced to simulate the model with imaginary theta. Two different definitions of the topological charge on the lattice have been used; one of them needs renormalization to match the continuum operator. Our work also offers a successful test for numerical methods based on analytic continuation.
Keywords
Cite
@article{arxiv.0711.1496,
title = {Mass gap in the 2D O(3) non-linear sigma model with a theta=pi term},
author = {B. Alles and A. Papa},
journal= {arXiv preprint arXiv:0711.1496},
year = {2008}
}
Comments
Latex file, 4 pages. To appear in PRD; it contains the justification of analicity, more details about the fits, more references, etc