Lee-Yang zero distribution of high temperature QCD and the Roberge-Weiss phase transition
Lee-Yang zero distribution of high temperature QCD and the Roberge-Weiss phase transition
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高温 QCD 的 Lee-Yang 零分布和 Roberge-Weiss 相变
DOI：
10.1103/physrevd.91.094507
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
S. M. Nishigaki
中科院分区：
文献类型：
--
作者：
K. Nagata;K. Kashiwa;A. Nakamura;S. M. Nishigaki
研究了有限密度和高温下 QCD 的正则配分函数和 Lee-Yang 零点。最近的晶格模拟证实，QCD 的自由能是在略高于伪临界温度的温度下夸克化学势的四次函数，就像自由无质量费米子气体的情况一样。我们使用鞍点近似提出了此类自由能的正则配分函数和 Lee-Yang 零点的解析推导。我们还使用费米子行列式的逸度展开以规范方法进行晶格 QCD 模拟，并仔细检查其可靠性。通过比较解析结果和数值结果，我们得出结论，正则配分函数遵循重子数的高斯分布，并且这些正则配分函数的Lee-Yang零点的积累表现出一阶Roberge-Weiss相变。我们讨论了结果的有效性和适用范围及其对理论和实验研究的影响。
Canonical partition functions and Lee-Yang zeros of QCD at finite density and high temperature are studied. Recent lattice simulations confirm that the free energy of QCD is a quartic function of quark chemical potential at temperature slightly above pseudocritical temperature, as in the case with a gas of free massless fermions. We present analytic derivation of the canonical partition functions and Lee-Yang zeros for this type of free energy using the saddle point approximation. We also perform lattice QCD simulation in a canonical approach using the fugacity expansion of the fermion determinant and carefully examine its reliability. By comparing the analytic and numerical results, we conclude that the canonical partition functions follow the Gaussian distribution of the baryon number, and the accumulation of Lee-Yang zeros of these canonical partition functions exhibit the first-order Roberge-Weiss phase transition. We discuss the validity and applicable range of the result and its implications both for theoretical and experimental studies.