Adjoint torelons, and the persistence of color electric flux tubes in the deconfined phase

TL;DR

This paper investigates the behavior of adjoint torelon loops in lattice QCD, revealing that long color electric flux tubes may persist beyond the deconfinement transition, indicating a gradual melting process into a gluon plasma.

Contribution

It introduces the adjoint torelon loop as a sensitive observable for detecting long electric flux tubes at high temperatures, providing new insights into the deconfinement transition.

Findings

Adjoint torelon loop peaks sharply at deconfinement transition.

Long electric flux tubes persist above T_c, diminishing around 2T_c.

Eigenvalues of Polyakov loops tend to attract in the confinement phase.

Abstract

It is argued that the adjoint torelon loop, i.e. a Polyakov loop in the adjoint representation running in a spatial, rather than temporal, direction, is an observable which is sensitive to the presence of long color electric flux tubes at high temperatures. We show via lattice Monte Carlo simulations that this observable has a sharp peak at the deconfinement transition, remains much larger than the vacuum value for some range of $T>T_c$, and falls below the vacuum value for $T > 2T_c$. This result suggests that long electric flux tubes may persist for a finite range of temperatures past the deconfinement transition, and at some stage disappear, presumably melting into a plasma of gluons. As a side remark, we point out that our results at $T<T_c$ imply that the eigenvalues of ordinary Polyakov loop holonomies in the confinement phase have a slight tendency to attract rather than repel, which may be relevant to certain models of confinement.