Lattice QCD at finite temperature and density in the phase-quenched approximation.
Lattice QCD at finite temperature and density in the phase-quenched approximation.
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相淬火近似中有限温度和密度下的晶格 QCD。
DOI：
10.1103/physrevd.77.114503
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发表时间：
2007
影响因子：
5
通讯作者：
D. Sinclair
中科院分区：
文献类型：
--
作者：
J. Kogut;D. Sinclair
有限夸克数化学势下的QCD具有复杂的费米子行列式，这使得标准格点QCD模拟无法对其进行研究。因此，我们模拟格点QCD在有限{mu}的相位淬火近似，取代费米子行列式与其幅度。(The相位猝灭近似可以被认为是在有限的同位旋化学势2{mu}下模拟N{sub f}/2 u型和N{sub f}/2 d型夸克味。这些模拟用于研究小{mu}的有限温度转变，其中有一些证据表明这种转变的位置（以及可能的性质）不受这种近似的影响。我们寻找3味QCD的预期关键终点。在这里，有人认为，零{mu}的临界点将成为小{mu}的临界终点，因为夸克质量刚刚超过临界质量。我们的模拟表明，这不会发生，并且对于小{mu}没有这样的关键终点。我们讨论了如何适应技术用于虚{mu}，以提高信号/噪声比，并加强我们的结论，使用相对较低的统计研究的结果。
QCD at a finite quark-number chemical potential {mu} has a complex fermion determinant, which precludes its study by standard lattice QCD simulations. We therefore simulate lattice QCD at finite {mu} in the phase-quenched approximation, replacing the fermion determinant with its magnitude. (The phase-quenched approximation can be considered as simulating at finite isospin chemical potential 2{mu} for N{sub f}/2 u-type and N{sub f}/2 d-type quark flavors.) These simulations are used to study the finite-temperature transition for small {mu}, where there is some evidence that the position (and possibly the nature) of this transition is unchanged by this approximation. We look for the expected critical endpoint for 3-flavor QCD. Here, it has been argued that the critical point at zero {mu} would become the critical endpoint at small {mu}, for quark masses just above the critical mass. Our simulations indicate that this does not happen, and there is no such critical endpoint for small {mu}. We discuss how we might adapt techniques used for imaginary {mu} to improve the signal/noise ratio and strengthen our conclusions, using results from relatively low statistics studies.