Abstract
We study the color correlation between static quark and antiquark ($q\bar q$) in the confined phase via reduced density matrices $\rho$ defined in color space. We adopt the standard Wilson gauge action and perform quenched calculations with the Coulomb gauge condition for reduced density matrices. The spatial volumes are $L^3 = 8^3$, $16^3$, $32^3$ and $48^3$, with the gauge couplings $\beta = 5.7$, 5.8 and 6.0. Each element of the reduced density matrix in the sub space of quarks' color degrees of freedom of the $q\bar q$ pair is calculated from staples defined by link variables. As a result, we find that $\rho$ is well written by a linear combination of the strongly correlated $q\bar q$ pair state with the color-singlet component and the uncorrelated $q\bar q$ pair state with random color configurations. We compute the Renyi entropies $S^{\rm Renyi}$ from $\rho$ to investigate the $q\bar q$ distance dependence of the color correlation of the $q\bar q$ pair and find that the color correlation is quenched as the distance increases.
Highlights
Color confinement is one of the nonperturbative features of QCD, the fundamental theory of the strong interaction
We study the color correlation between the static quark and antiquark in the confined phase via reduced density matrices ρ defined in color space
The color charge first associated with a color-singlet qqpair flows into the interquark flux tube as the qqseparation is enlarged, keeping the total system color singlet [4,5]
Summary
Color confinement is one of the nonperturbative features of QCD, the fundamental theory of the strong interaction. The static interquark potential (qqpotential) in the confinement phase exhibits a linearly rising potential in the largeseparation limit giving the diverging energy, and quarks cannot be isolated. If the color charge of the qqpart and that of the gluon part are separately considered, this color transfer can be regarded as a color charge leak from the qqpart to the gluon part in association with the screening effect This color leak should depend on the qqdistance and would be observed as the distance dependence of the color correlation between the quark and antiquark. Such color correlation of the qqpair may be detected by entanglement entropy (EE) defined by the reduced density matrix.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
