Polyakov loop effects on the phase diagram in strong-coupling lattice QCD
Résumé
We investigate the Polyakov loop effects on the QCD phase diagram by using the strong-coupling (1/g2) expansion of the lattice QCD (SC-LQCD) with one species of unrooted staggered quark, including O(1/g4) effects. We take account of the effects of Polyakov loop fluctuations in Weiss mean-field approximation (MFA), and compare the results with those in the Haar-measure MFA (no fluctuation from the mean-field). The Polyakov loops strongly suppress the chiral transition temperature in the second-order/crossover region at small chemical potential (μ), while they give a minor modification of the first-order phase boundary at larger μ. The Polyakov loops also account for a drastic increase of the interaction measure near the chiral phase transition. The chiral and Polyakov loop susceptibilities (χσ,χℓ) have their peaks close to each other in the second-order/crossover region. In particular in Weiss MFA, there is no indication of the separated deconfinement transition boundary from the chiral phase boundary at any μ. We discuss the interplay between the chiral and deconfinement dynamics via the bare quark mass dependence of susceptibilities χσ,ℓ.
Mots clés
11.15.Me
12.38.Gc
11.10.Wx
25.75.Nq
Polyakov loop: effect
expansion: strong coupling
potential: chemical
Polyakov loop: susceptibility
critical phenomena: chiral
transition: chiral
quantum chromodynamics: critical phenomena
temperature: transition
quark: mass dependence
interaction: measure
quark: staggered
mean field approximation
lattice field theory
susceptibility: chiral
deconfinement
fluctuation
Origine : Fichiers produits par l'(les) auteur(s)
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