标题： 同位旋QCD中声速峰和一致性上的热效应 显示英文标题

标题： Thermal effects on sound velocity peak and conformality in isospin QCD

摘要： 我们研究了在等位电荷QCD中热效应对于状态方程（EOS）的影响，利用了一个与Polyakov环耦合的夸克-介子模型。 该夸克-介子模型在单环近似下进行分析，这是包含介子凝聚在有限等位电荷密度下夸克子结构约束的最小阶数。 在之前的研究中，我们表明在零温度下，夸克-介子模型在低密度的手征有效理论区域和高密度的微扰QCD区域之间的区域内产生了声速峰值和负迹异常，与格点模拟结果合理一致。 我们现在引入来自夸克的热效应，在Polyakov环背景中研究状态方程，特别是沿等熵轨迹的声速和迹异常。 在大等位电荷密度下，存在三个温度窗口； (i) 几乎消失的Polyakov环的介子凝聚区域，(ii) 具有有限Polyakov环的介子凝聚区域，以及(iii) 没有介子凝聚的夸克气体区域。 在区域(i)中，与介子凝聚相关的能隙强烈抑制热激发。 当系统接近区域(ii)时，作为非相对论粒子行为的热夸克增加能量密度但压力很小，显著降低声速至小于共形值，同时使迹异常增加到正值。 接近区域(iii)时，随着介子凝聚的熔化，热夸克变得更加相对论性，声速向共形极限增加。 也简要讨论了来自热介子的修正。 显示英文摘要

摘要： We study thermal effects on equations of state (EOS) in isospin QCD, utilizing a quark-meson model coupled to a Polyakov loop. The quark-meson model is analyzed at one-loop that is the minimal order to include quark substructure constraints on pions which condense at finite isospin density. In the previous study we showed that the quark-meson model at zero temperature produces the sound velocity peak and the negative trace anomaly in the domain between the chiral effective theory regime at low density and the perturbative QCD regime at high density, in reasonable agreement with lattice simulations. We now include thermal effects from quarks in the Polyakov loop background and examine EOS, especially the sound velocity and trace anomaly along isentropic trajectories. At large isospin density, there are three temperature windows; (i) the pion condensed region with almost vanishing Polyakov loops, (ii) the pion condensed region with finite Polyakov loops, and (iii) the quark gas without pion condensates. In the domain (i), the gap associated with the pion condensate strongly quenches thermal excitations. As the system approaches the domain (ii), thermal quarks, which behave as non-relativistic particles, add energy density but little pressure, substantially reducing the sound velocity to the value less than the conformal value while increasing the trace anomaly toward the positive value. Approaching the domain (iii), thermal quarks become more relativistic as pion condensates melt, increasing sound velocity toward the conformal limit. Corrections from thermal pions are also briefly discussed.