Functional Renormalization Group Study of Phonon Mode Effects on Chiral Critical Point

Abstract

We apply the functional renormalization-group (FRG) equation to analyze the nature of the QCD critical point beyond the mean-field approximation by taking into consideration the fact that the soft mode associated with the QCD critical point is a linear combination of fluctuations of the chiral condensate and the quark-number density, rather than the pure chiral fluctuations. We first construct an extended quark-meson model in which a new field corresponding to quark-number density is introduced to the conventional one composed of the chiral fields sigma, pi and the quarks. The fluctuations of the quark-number density as well as the chiral condensate are taken into account by solving the FRG equation which contains sigma and the new field as coupled dynamical variables. It is found that the mixing of the two dynamical variables causes a kind of level repulsion between the curvature masses, which in turn leads to an expansion of the critical region of the QCD critical point, depending on the coupling constants in the model yet to be determined from microscopic theories or hopefully by experiments.

16 pages, 6 figures

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Cited by in corpus (13)

• The nonperturbative functional renormalization group and its applications
• The QCD phase structure at finite temperature and density
• QCD at finite temperature and density within the fRG approach: An overview
• Functional renormalization group analysis of the soft mode at the QCD critical point
• Functional renormalization group study of the Quark-Meson model with $\omega$ meson
• Fluctuations in cool quark matter and the phase diagram of Quantum Chromodynamics
• Net quark number probability distribution near the chiral crossover transition
• Shocks and quark-meson scatterings at large density
• Tachyonic instability of the scalar mode prior to QCD critical point based on Functional renormalization-group method
• Thermalization and dynamical spectral properties in the quark-meson model
• Momentum scale dependence of the net quark number fluctuations near chiral crossover
• Influence of the vector interaction and an external magnetic field on the isentropes near the chiral critical end point
• Emergence of soft quark excitations by the coupling with a soft mode of the QCD critical point