Probing vortex unbinding via dipole fluctuations

H. A. Fertig, Joseph P. Straley

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


We develop a numerical method for detecting a vortex-unbinding transition in a two-dimensional system by measuring large-scale fluctuations in the total vortex dipole moment P of the system. These are characterized by a quantity ℱ that measures the number of configurations in a simulation for which either Px or Py is half the system size. It is shown that ℱ tends to a nonvanishing constant for large system sizes in the unbound phase, and vanishes in the bound phase. The method is applied to the XY model both in the absence and in the presence of a magnetic field. In the latter case, the system size dependence of ℱ suggests that there exist three distinct phases, one unbound vortex phase, a logarithmically bound phase, and a linearly bound phase.

Original languageEnglish
Article number201402
Pages (from-to)2014021-2014024
Number of pages4
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number20
StatePublished - Nov 15 2002

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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