Fighting topological freezing in the two-dimensional CPN−1 model

Martin Hasenbusch

doi:10.1051/epjconf/201817502004

EPJ

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Proceedings

Open Access

EPJ Web of Conferences 175, 02004 (2018)
https://doi.org/10.1051/epjconf/201817502004

Fighting topological freezing in the two-dimensional CP^N−1 model

Martin Hasenbusch^,*

Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin, Germany

Published online: 26 March 2018

Abstract

We perform Monte Carlo simulations of the CP^N−1 model on the square lattice for N = 10, 21, and 41. Our focus is on the severe slowing down related to instantons. To fight this problem we employ open boundary conditions as proposed by Lüscher and Schaefer for lattice QCD. Furthermore we test the efficiency of parallel tempering of a line defect. Our results for open boundary conditions are consistent with the expectation that topological freezing is avoided, while autocorrelation times are still large. The results obtained with parallel tempering are encouraging.

Acknowledges financial support by the Deutsche Forschungsgemeinschaft (DFG) under the grant No HA 3150/4-1.

© The Authors, published by EDP Sciences, 2018

This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (http://creativecommons.org/licenses/by/4.0/).