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arXiv 1312.3286hep-latcond-mat.dis-nn
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QCD Dirac谱迁移率边缘的临界统计

Critical statistics at the mobility edge of QCD Dirac spectra

Shinsuke M. Nishigaki, Matteo Giordano, Tamas G. Kovacs, Ferenc Pittler

摘要:

我们研究了在临界温度以上QCD Dirac谱近边部分本征值的统计涨落。为了完整性,我们开始审查的非线性西格玛模型和随机矩阵描述的安德森紧束缚哈密顿量的光谱性质,并在迁移率边缘的尺度不变的中间谱统计。通过拟合的水平间距分布,变形的随机矩阵合奏模型的多重分形波函数的典型的安德森局域化过渡,示出这样一个关键的统计提供了一个很好的有效的描述。接下来,我们将上述安德森哈密顿量的策略推广到狄拉克谱。对于在物理点处具有2+1味动力学夸克的QCD和SU(2)猝灭规范理论的交错Dirac算符,我们确定了迁移率边的精确位置作为能级间距分布的标度不变不动点。流动性边缘周围的本征值服从上述变形的随机矩阵合奏酉类和辛类所描述的临界统计。QCD在物理点处的最佳拟合形变参数与么正类中的Anderson哈密顿量一致。最后,我们提出了一种利用变形手征随机矩阵的本征值分布来确定QCD Dirac谱在临界温度附近的迁移率边的方法。

英文摘要:

We examine statistical fluctuation of eigenvalues from the near-edge bulk of QCD Dirac spectra above the critical temperature. For completeness we start by reviewing on the spectral property of Anderson tight-binding Hamiltonians as described by nonlinear sigma models and random matrices, and on the scale-invariant intermediate spectral statistics at the mobility edge. By fitting the level spacing distributions, deformed random matrix ensembles which model multifractality of the wave functions typical of the Anderson localization transition, are shown to provide an excellent effective description for such a critical statistics. Next we carry over the above strategy for the Anderson Hamiltonians to the Dirac spectra. For the staggered Dirac operators of QCD with 2+1 flavors of dynamical quarks at the physical point and of SU(2) quenched gauge theory, we identify the precise location of the mobility edge as the scale-invariant fixed point of the level spacing distribution. The eigenvalues around the mobility edge are shown to obey critical statistics described by the aforementioned deformed random matrix ensembles of unitary and symplectic classes. The best-fitting deformation parameter for QCD at the physical point turns out to be consistent with the Anderson Hamiltonian in the unitary class. Finally, we propose a method of locating the mobility edge at the origin of QCD Dirac spectrum around the critical temperature, by the use of individual eigenvalue distributions of deformed chiral random matrices.

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