A new method to analytically determine the partition function zeroes of weakly coupled theories on finite-size lattices is developed. Applied to the lattice Schwinger model, this reveals the possible absence of a phase transition at fixed weak coupling. We show how finite-size scaling techniques on small or moderate lattice sizes may mimic the presence of a spurious phase transition. Application of our method to the Gross-Neveu model yields a phase diagram consistent with that coming from a saddle point analysis.
Bibliographical noteThe full text is also available from: http://de.arxiv.org/abs/hep-lat/9909161
NOTICE: this is the author’s version of a work that was accepted for publication in Nuclear Physics B - Proceedings Supplements. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Nuclear Physics B - Proceedings Supplements, [83-84, 2000] DOI: 10.1016/S0920-5632(00)91770-5.
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