Flux tubes in QCD at finite temperature

Abstract

We present results for the chromo-electric field generated by a static quark-antiquark pair at finite temperature, in lattice QCD with 2+1 dynamical staggered fermions at physical quark masses. We investigate the evolution of the field as the temperature increases through and beyond the chiral transition. For all the temperatures considered we find clear evidence of a chromo-magnetic current and of a longitudinal nonperturbative chromo-electric field that stays almost uniform along the flux tube. In the high-temperature region the magnitude of the flux-tube field is determined by an effective string tension that decreases exponentially as the temperature increases, while the flux-tube width decreases according to an inverse-temperature law. Our results suggest that beyond the chiral pseudocritical temperature the quark-antiquark system can be characterized by a screened string tension.

Figures (7)

• Figure 1: The flux-tube operator with the Schwinger line attached to the quark time line (left) or to the antiquark time line (right).
• Figure 2: The $E_x$ field component for $x_l=4a \simeq 0.385$ fm, at $\beta=6.880$, $48^4$ lattice, $d \simeq 0.963$ fm, versus HYP3d smearing steps.
• Figure 3: Scaling check at $T \simeq 205$ MeV and $d \simeq 0.963$ fm for the full longitudinal electric field $E_x$ (left) and its nonperturbative component $E_x^{\rm NP}$ (right).
• Figure 4: The full profile of $E_x^{\rm NP}$ field at $\beta=6.880$, $d=10a \simeq 0.963$ fm, in correspondence of increasing temperatures: $T \simeq 43,128,146,171,205,256,342,512$ MeV (from left to right, from top to bottom).
• Figure 5: $E_x^{\rm NP}$ field on the transverse midplane for increasing temperatures: $T \simeq 43,128,146,171,205,256,342,512$ MeV .