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arXiv · hep-lat/0311033

The photon propagator in compact QED_{2+1}: the effect of wrapping Dirac strings

M. N. Chernodub·E. -M. Ilgenfritz·A. Schiller
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Abstract

We discuss the influence of closed Dirac strings on the photon propagator in the Landau gauge emerging from a study of the compact U(1) gauge model in 2+1 dimensions. This gauge also minimizes the total length of the Dirac strings. Closed Dirac strings are stable against local gauge-fixing algorithms only due to the torus boundary conditions of the lattice. We demonstrate that these left-over Dirac strings are responsible for the previously observed unphysical behavior of the propagator of space-like photons (D_T) in the deconfinement (high temperature) phase. We show how one can monitor the number N_3 of thermal Dirac strings which allows to separate the propagator measurements into N_3 sectors. The propagator in N_3 \neq 0 sectors is characterized by a non--zero mass and an anomalous dimension similarly to the confinement phase. Both mass squared and anomalous dimension are found to be proportional to N_3. Consequently, in the N_3=0 sector the unphysical behavior of the D_T photon propagator is cured and the deviation from the free massless propagator disappears.

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M. N. Chernodub, E. -M. Ilgenfritz, A. Schiller. 2003-11-21. The photon propagator in compact QED_{2+1}: the effect of wrapping Dirac strings. https://doi.org/10.1103/physrevd.69.094502

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