title: First-order phase transitions from poles in asymptotic representations of partition functions.
abstract: Although partition functions of finite-size systems are always analytic, and hence have no poles, they can be expressed in many cases as series containing terms with poles. Here we show that such poles can be related to linear branches of the entropy, expressed in the thermodynamic limit as a function of the energy per particle. We also show that these poles can be used to determine whether the entropy is nonconcave or has linear parts, which is something that cannot be done with the sole knowledge of the thermodynamic free energy derived from the partition function. We discuss applications for equilibrium systems having first-order phase transitions.
authors.affiliation: School of Mathematical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom. ht@maths.qmul.ac.uk
authors.forename: Hugo
authors.initials: H
authors.lastname: Touchette
authors.forename: Rosemary J
authors.initials: RJ
authors.lastname: Harris
authors.forename: Julien
authors.initials: J
authors.lastname: Tailleur
mesh_terms: D003198:Computer Simulation; D008956:Models, Chemical; D044367:Phase Transition; D013816:Thermodynamics