Show simple item record Banerjee, D Chandrasekharan, S 2011-06-21T17:27:47Z 2010-06-08
dc.identifier.citation Physical Review D - Particles, Fields, Gravitation and Cosmology, 2010, 81 (12)
dc.identifier.issn 1550-7998
dc.description.abstract In the presence of a chemical potential, the physics of level crossings leads to singularities at zero temperature, even when the spatial volume is finite. These singularities are smoothed out at a finite temperature but leave behind nontrivial finite size effects which must be understood in order to extract thermodynamic quantities using Monte Carlo methods, particularly close to critical points. We illustrate some of these issues using the classical nonlinear O(2) sigma model with a coupling β and chemical potential μ on a 2+1-dimensional Euclidean lattice. In the conventional formulation this model suffers from a sign problem at nonzero chemical potential and hence cannot be studied with the Wolff cluster algorithm. However, when formulated in terms of the worldline of particles, the sign problem is absent, and the model can be studied efficiently with the "worm algorithm." Using this method we study the finite size effects that arise due to the chemical potential and develop an effective quantum mechanical approach to capture the effects. As a side result we obtain energy levels of up to four particles as a function of the box size and uncover a part of the phase diagram in the (β,μ) plane. © 2010 The American Physical Society.
dc.language.iso en_US en_US
dc.relation.ispartof Physical Review D - Particles, Fields, Gravitation and Cosmology
dc.relation.isversionof 10.1103/PhysRevD.81.125007
dc.title Finite size effects in the presence of a chemical potential: A study in the classical nonlinear O(2) sigma model
dc.title.alternative en_US
dc.type Journal Article
dc.description.version Version of Record en_US 2010-6-8 en_US
duke.description.endpage 125007 en_US
duke.description.issue 12 en_US
duke.description.startpage 125007 en_US
duke.description.volume 81 en_US
dc.relation.journal Physical Review D en_US
pubs.issue 12
pubs.organisational-group /Duke
pubs.organisational-group /Duke/Trinity College of Arts & Sciences
pubs.organisational-group /Duke/Trinity College of Arts & Sciences/Physics
pubs.publication-status Published
pubs.volume 81
dc.identifier.eissn 1550-2368

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