The Fredenhagen-Marcu operator in the gauge-Higgs Z(2) LGT at finite temperature

Abstract

We explore the possibility to use the Fredenhagen-Marcu operator as a candidate order parameter of the deconfinement phase transition in gauge matter systems at finite temperature. Concretely, we compute by numerical simulations this operator in the (2+1)-dimensional Z(2) lattice gauge theory (LGT) with Z(2) gauge fields coupled to Z(2)-valued Higgs fields. While we cannot provide an unambiguous evidence, we present some hints that the Fredenhagen-Marcu operator is capable of distinguishing the deconfinement phase from the Higgs and confinement phases of the theory.

28 pages, 12 figures, 9 tables; revised version with extended text, additional figures and tables, and an appendix; version published in Phys. Lett. B