N f =2 QCD chiral phase transition with Wilson fermions at zero and imaginary chemical potential
N f =2 QCD chiral phase transition with Wilson fermions at zero and imaginary chemical potential
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DOI：
10.1103/physrevd.93.114507
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发表时间：
2016-02
影响因子：
5
通讯作者：
O. Philipsen;C. Pinke
中科院分区：
文献类型：
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作者：
O. Philipsen;C. Pinke
具有两种动力学性质的夸克的量子色动力学(QCD)手征极限的热相变的级数是一个长期存在的问题，在连续谱极限中仍是未知的。相变是一阶还是二阶对于QCD相图和有限密度下临界终点的存在有着重要的意义。我们遵循最近提出的一种方法，在虚化学势下显式确定一阶手征跃迁的区域，并将其外推到具有已知临界指数的零化学势。在粗糙的$N_t=4$晶格上使用未经改进的威尔逊费米子，一阶区变得很大，不需要外推。临界介子质量$m\pi^c约为560$MeV，比使用交错费米子的临界介子质量大近10倍。我们的结果与用改进的威尔逊费米子研究三味QCD是一致的，并表明双味手性跃迁的系统误差仍然是100量级。
The order of the thermal phase transition in the chiral limit of Quantum Chromodynamics (QCD) with two dynamical flavors of quarks is a long-standing issue and still not known in the continuum limit. Whether the transition is first or second order has important implications for the QCD phase diagram and the existence of a critical endpoint at finite densities. We follow a recently proposed approach to explicitly determine the region of first order chiral transitions at imaginary chemical potential, where it is large enough to be simulated, and extrapolate it to zero chemical potential with known critical exponents. Using unimproved Wilson fermions on coarse $N_t=4$ lattices, the first order region turns out to be so large that no extrapolation is necessary. The critical pion mass $m_\pi^c\approx 560$ MeV is by nearly a factor 10 larger than the corresponding one using staggered fermions. Our results are in line with investigations of three-flavour QCD using improved Wilson fermions and indicate that the systematic error on the two-flavour chiral transition is still of order 100\%.