论文标题
在晶格上的状态和速度QCD的状态和速度
Equation of state and speed of sound of isospin-asymmetric QCD on the lattice
论文作者
论文摘要
我们在晶格上的光夸克化学电位之间存在异种不对称的情况下确定在非零温度下状态的QCD方程。我们的模拟使用三个不同的晶格间距采用$ n_f = 2+1 $的动态交错夸克风味。主要结果是基于同胞蛋白密度的二维样条插值，可以通过分析获得所有相关数量。特别是，我们提出了压力，相互作用度量，能量和熵密度以及声速的结果。值得注意的是，后者被发现超过其在pion凝结阶段深处的理想气体极限，这是第一个原理中违反该限制的第一个说明。最后，我们还首次在温度下计算相图。所有可观察物的数据对于有效理论的基准和QCD的低能模型将很有用，并且在辅助文件中提供了简单的重复使用。
We determine the QCD equation of state at nonzero temperature in the presence of an isospin asymmetry between the light quark chemical potentials on the lattice. Our simulations employ $N_f=2+1$ flavors of dynamical staggered quarks at physical masses, using three different lattice spacings. The main results are based on a two-dimensional spline interpolation of the isospin density, from which all relevant quantities can be obtained analytically. In particular, we present results for the pressure, the interaction measure, the energy and entropy densities, as well as the speed of sound. Remarkably, the latter is found to exceed its ideal gas limit deep in the pion condensed phase, the first account of the violation of this limit in first principles QCD. Finally, we also compute the phase diagram in the temperature -- isospin density plane for the first time. The data for all observables will be useful for the benchmarking of effective theories and low-energy models of QCD and are provided in ancillary files for simple reuse.
