Reduction of the sign problem using the meron-cluster approach
2003 (English)In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics, ISSN 1063-651X, E-ISSN 1095-3787, Vol. 68, 016122-1-016122-8 p.Article in journal (Refereed) Published
The sign problem in quantum Monte Carlo calculations is analyzed using the meron-cluster solution. A meron is a loop that alters the sign of the configuration, and the concept of merons can be used to solve the sign problem for a limited class of models. Here we show that the method can be used to reduce the sign problem in a wider class of models. We investigate how the meron solution evolves between a point in parameter space where it eliminates the sign problem and a point where it does not affect the sign problem at all. In this intermediate regime, the merons can be used to reduce the sign problem. The average sign still decreases exponentially with system size and inverse temperature, but with a different prefactor. The sign exhibits the slowest decrease in the vicinity of points where the meron-cluster solution eliminates the sign problem. We have used stochastic series expansion quantum Monte Carlo combined with the concept of directed loops.
Place, publisher, year, edition, pages
2003. Vol. 68, 016122-1-016122-8 p.
QUANTUM MONTE-CARLO; SPIN SYSTEMS; SIMULATIONS; MODELS
Condensed Matter Physics
IdentifiersURN: urn:nbn:se:kth:diva-6796DOI: 10.1103/PhysRevE.68.016122ISI: 000184582500032OAI: oai:DiVA.org:kth-6796DiVA: diva2:11607
QC 201006282007-02-202007-02-202012-01-19Bibliographically approved