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Heiko Feldmann

Publications and source records attributed to Heiko Feldmann.

2 recordsLinked to original sources
arXiv1997

Complex-Temperature Partition Function Zeros of the Potts Model on the Honeycomb and Kagomé Lattices

We calculate complex-temperature (CT) zeros of the partition function for the $q$-state Potts model on the honeycomb and kagomé lattices for several values of $q$. These give information on the CT phase diagrams. A comparison of results obtained for different boundary conditions and a discussion of some CT singularities are given. Among other results, our findings show that the Potts antiferromagnet with $q=4$ and $q=5$ on the kagomé lattice has no phase transition at either finite or zero temperature.

cond-mat.stat-mech↗
arXiv1997

A Mapping Relating Complex and Physical Temperatures in the 2D $q$-state Potts Model and Some Applications

We show an exact equivalence of the free energy of the $q$-state Potts antiferromagnet on a lattice $Λ$ for the full temperature interval $0 \le T \le \infty$ and the free energy of the $q$-state Potts model on the dual lattice for a semi-infinite interval of complex temperatures (CT). This implies the existence of two quite different types of CT singularities: the generic kind, which does not obey universality or various scaling relations, and a special kind which does obey such properties and encodes information of direct physical relevance. We apply this observation to characterize CT properties of the Potts model on several lattices, to rule out two existing conjectures, and to determine the critical value of $q$ above which the Potts antiferromagnet on the diced lattice has no phase transition.

cond-mat.stat-mech↗