title: Winding number excitation detects phase transition in one-dimensional XY model with variable interaction range.
abstract: We numerically study the critical behavior of the one-dimensional XY model of the size N with variable interaction range L. As expected, the standard local order parameter of the magnetization is shown to well detect the mean-field-type transition which occurs at any nonzero value of L/N. The system is particularly interesting since the underlying one-dimensional structure allows us to study the topological excitation of the winding number across the whole system even though the system shares the mean-field transition with the globally coupled system. We propose a nonlocal order parameter based on the width of the winding number distribution which exhibits a clear signature of the transition nature of the system.
authors.affiliation: Department of Physics and Research Institute of Physics and Chemistry, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: Hyunsuk
authors.initials: H
authors.lastname: Hong
authors.affiliation: Department of Physics, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
authors.forename: Beom Jun
authors.initials: BJ
authors.lastname: Kim