arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0909.4782hep-thhep-phnucl-th
收藏

Sakai-Sugimoto模型中的反常和手征磁效应

Anomalies and the chiral magnetic effect in the Sakai-Sugimoto model

Anton Rebhan, Andreas Schmitt, Stefan A. Stricker

摘要:

在手征磁效应中,左右手夸克数量的不平衡会产生一个电磁流,它与非中心重离子碰撞产生的磁场平行。手征不平衡可能是由拓扑非平凡的胶子组态通过QCD轴向异常引起的,而由此产生的电磁流本身是QED异常的结果。在Sakai-Sugimoto模型中,我们讨论了QED轴向反常的正确实现,手征流的(模糊)定义,手征磁效应的计算,该模型在一定范围内是大N_c QCD的对偶。我们发现,这个模型正确地包含所谓的一致异常,但需要引入(全息)有限的反项,以产生正确的协变异常。通过轴向化学势引入净手征,我们发现只有在包括这个反项之前才有一个非零矢量流。这似乎意味着在这个模型中没有手征磁效应。另一方面,对于一个传统的夸克化学势和大的磁场,这是感兴趣的致密星的物理,我们得到了一个非平凡的结果的轴向电流是与以前的计算和已知的QCD的精确结果。

英文摘要:

In the chiral magnetic effect an imbalance in the number of left- and right-handed quarks gives rise to an electromagnetic current parallel to the magnetic field produced in noncentral heavy-ion collisions. The chiral imbalance may be induced by topologically nontrivial gluon configurations via the QCD axial anomaly, while the resulting electromagnetic current itself is a consequence of the QED anomaly. In the Sakai-Sugimoto model, which in a certain limit is dual to large-N_c QCD, we discuss the proper implementation of the QED axial anomaly, the (ambiguous) definition of chiral currents, and the calculation of the chiral magnetic effect. We show that this model correctly contains the so-called consistent anomaly, but requires the introduction of a (holographic) finite counterterm to yield the correct covariant anomaly. Introducing net chirality through an axial chemical potential, we find a nonvanishing vector current only before including this counterterm. This seems to imply the absence of the chiral magnetic effect in this model. On the other hand, for a conventional quark chemical potential and large magnetic field, which is of interest in the physics of compact stars, we obtain a nontrivial result for the axial current that is in agreement with previous calculations and known exact results for QCD.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑