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 an 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. Our conclusion is that the Fredenhagen-Marcu operator can indeed serve as an order parameter capable of distinguishing the deconfinement phase from the Higgs and confinement phases of the theory.