标题： 格点QCD中虚化学势和实化学势下的夸克密度$_2$D 显示英文标题

标题： Quark Density in Lattice QC$_2$D at Imaginary and Real Chemical Potential

摘要： 我们研究了具有两种味交错费米子的格点双色QCD（QC$_2$D），分别在虚数和实数夸克化学势 $\mu_q$ 和 $T>T_c$ 下。 我们采用多种方法从虚数到实数夸克化学势 $\mu_q$ 对夸克数密度进行外推，包括级数展开以及基于唯象模型的解析延拓，并通过与格点数据的比较来研究这些方法的准确性。 在罗伯格-韦斯温度 $T<T_{RW}$ 以下，我们发现聚类展开模型在所研究的化学势范围内提供了精确的重子数密度解析延拓。 另一方面，重建规范配分函数的行为表明，现有的模型在高夸克密度下可能需要修正。 在$T>T_{RW}$，我们证明了基于三角函数将$\mu_q$的解析延拓到实数值的方法与基于$\mu_q$幂级数展开的传统方法同样有效。 显示英文摘要

摘要： We study lattice two-color QCD (QC$_2$D) with two flavors of staggered fermions at imaginary and real quark chemical potential $\mu_q$ and $T>T_c$. We employ various methods of extrapolation of the quark number density from imaginary to real quark chemical potentials $\mu_q$, including series expansions as well as analytic continuation based on phenomenological models, and study their accuracy by comparing the results to the lattice data. Below the Roberge-Weiss temperature, $T<T_{RW}$, we find that the cluster expansion model provides an accurate analytic continuation of the baryon number density in the studied range of chemical potentials. On the other hand, the behavior of the reconstructed canonical partition functions indicates that the available models may require corrections at high quark densities. At $T>T_{RW}$ we show that the analytic continuation to the real values of $\mu_q$ based on trigonometric functions works equally well with the conventional method based on the Taylor expansion in powers of $\mu_q$.