Regulator scheme dependence of the chiral phase transition at high densities

Abstract

A common feature of recent functional renormalization group investigations of effective low-energy QCD is the appearance of a back-bending behavior of the chiral phase transition line at low temperatures together with a negative entropy density in the symmetric regime. The regulator scheme dependence of this phenomenon and the necessary modifications at finite densities are analyzed within a two-flavor quark-meson model. The flows at finite densities for three different regulators of three- or four-dimensional momenta are confronted to each other. It is found that the back-bending behavior and the negative entropy density can be traced back to the explicit momentum dependence of the regulator shape function. While it persists for the often-used three-dimensional flat regulator, it vanishes for Callan-Symanzik type regulators. This points to truncation artifacts in the lowest order of the derivative expansion. A careful theoretical as well as numerical exploration is given.

16 pages, 6 figures, 1 table, to be published in PRD

References in corpus (19)

• Exact evolution equation for the effective potential
• Color superconductivity in dense quark matter
• Inhomogeneous chiral condensates
• Susceptibilities near the QCD (tri)critical point
• Renormalization Group Approach towards the QCD Phase Diagram
• Baryon number fluctuations at finite temperature and density
• QCD at finite temperature and density within the fRG approach: An overview
• Towards quantitative precision in the chiral crossover: masses and fluctuation scales
• From asymmetric nuclear matter to neutron stars: a functional renormalization group study
• Functional renormalization group study of the Quark-Meson model with $\omega$ meson
• Shocks and quark-meson scatterings at large density
• Vector and Axial-Vector Mesons in Nuclear Matter
• Numerical fluid dynamics for FRG flow equations: Zero-dimensional QFTs as numerical test cases. I. The $O(N)$ model
• Bose-Einstein condensation and Silver Blaze property from the two-loop $\Phi$-derivable approximation
• Numerical fluid dynamics for FRG flow equations: Zero-dimensional QFTs as numerical test cases. II. Entropy production and irreversibility of RG flows
• Precision calculation of universal amplitude ratios in $O(N)$ universality classes: Derivative Expansion results at order $\mathcal{O}({\partial }^4)$
• Numerical fluid dynamics for FRG flow equations: Zero-dimensional QFTs as numerical test cases. III. Shock and rarefaction waves in RG flows reveal limitations of the $N\to \infty$ limit in $O(N)$-type models
• From quarks and gluons to color superconductivity at supranuclear densities
• The regulator dependence in the functional renormalization group: a quantitative explanation

Cited by in corpus (2)

• QCD at finite temperature and density within the fRG approach: An overview
• Functional renormalization group for $p=2$ like glassy matrices in the planar approximation: II. Ward identities method in the deep IR