2008/06/30 by E. S. Fraga, Eduardo S. Fraga, C. Villavicencio
Physics and Astronomy · #High-Energy Particle Collisions Research #Quantum Chromodynamics and Particle Interactions #Statistical Mechanics and Entropy #hep-lat #hep-ph
paper · pdf · doi:10.1103/physrevd.81.065022
published as Phys.Rev.D81:065022,2010 · 5 pages, 2 figures. v2: title changed, expanded discussion and added example (calculation of <theta^2> at high temperature). Published in PRD
arxiv created 2010/03/19 · openalex publication_date 2010/03/19 · arxiv updated 2010/04/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We construct an effective action for QCD by expanding the quark determinant in powers of the chemical potential at finite temperature in the case of massless quarks. To cut the infinite series, we adopt the Weinberg power counting criteria. We compute the minimal effective action (\ensuremath∼p4), expanding in the external momentum, which implies the use of the hard thermal loop approximation. Our main result is a gauge invariant expression for the phase \ensuremathθ of the functional determinant in QCD and recovers dimensional reduction in the high-temperature limit. We compute, analytically, ⟨\ensuremathθ2⟩ in the range of p\ensuremath≪2\ensuremathπT, including perturbative and nonperturbative contributions, the latter treated within the mean field approximation. Implications for lattice simulations are briefly discussed.