ITEP, B. Cheremushkinskaya 25, Moscow, 117218, Russia.
Phys Rev Lett. 2010 Sep 24;105(13):132001. doi: 10.1103/PhysRevLett.105.132001. Epub 2010 Sep 20.
We study the correlator of two vector currents in quenched SU(2) lattice gauge theory with a chirally invariant lattice Dirac operator with a constant external magnetic field. It is found that in the confinement phase the correlator of the components of the current parallel to the magnetic field decays much slower than in the absence of a magnetic field, while for other components the correlation length slightly decreases. We apply the maximal entropy method to extract the corresponding spectral function. In the limit of zero frequency this spectral function yields the electric conductivity of quenched theory. We find that in the confinement phase the external magnetic field induces nonzero electric conductivity along the direction of the field, transforming the system from an insulator into an anisotropic conductor. In the deconfinement phase the conductivity does not exhibit any sizable dependence on the magnetic field.
我们研究了在外部恒定磁场中手征不变格点 Dirac 算子作用下被淬火的 SU(2)格点规范理论中两个矢量流的关联函数。我们发现，在禁闭相中，平行于磁场的电流分量的关联函数的衰减速度比没有磁场时慢得多，而对于其他分量，相关长度则略有减小。我们应用最大熵方法提取相应的谱函数。在零频率极限下，该谱函数给出淬火理论的电导率。我们发现，在禁闭相中，外磁场沿磁场方向诱导出非零的电导率，使系统从绝缘体转变为各向异性导体。在退禁闭相中，电导率对磁场没有任何显著的依赖关系。
