theta dependence of SU(N) gauge theories in the presence of a topological term
theta dependence of SU(N) gauge theories in the presence of a topological term
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DOI：
10.1088/1742-6596/110/12/122005
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发表时间：
2007-06
期刊：
影响因子：
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通讯作者：
L. Debbio;H. Panagopoulos;Ettore Vicari Supa;S. O. Physics;U. Edinburgh;D. Physics;U. O. Cyprus;University of Pisa
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文献类型：
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作者：
L. Debbio;H. Panagopoulos;Ettore Vicari Supa;S. O. Physics;U. Edinburgh;D. Physics;U. O. Cyprus;University of Pisa
本文综述了四维SU（N）规范理论和QCD的θ依赖性，其中θ是拉氏量中CP破坏拓扑项的系数。特别地，我们讨论了大N极限下的θ依赖性.大多数结果已经通过数值模拟得到的理论的晶格公式内。我们审查结果在零和有限的温度。我们的结果支持的情况下得到的一般大N标度参数，特别是Witten-Veneziano机制来解释U（1）A问题。我们还比较与其他方法得到的结果，特别是在大- N限制，其中的问题也得到了解决，例如，AdS/CFT对应。我们讨论了全QCD中与θ相关的问题：中子电偶极矩，拓扑磁化率对夸克质量的依赖，有限温度下U（1）A对称性破缺。我们还回顾了2D C P N-1模型的结果，这是一个有趣的理论实验室，研究与拓扑学相关的问题。最后讨论了拓扑电荷密度两点关联函数的主要特征。
Abstract We review results concerning the θ dependence of 4D S U ( N ) gauge theories and QCD, where θ is the coefficient of the CP-violating topological term in the Lagrangian. In particular, we discuss θ dependence in the large- N limit. Most results have been obtained within the lattice formulation of the theory via numerical simulations. We review results at zero and finite temperature. We show that the results support the scenario obtained by general large- N scaling arguments, and in particular the Witten–Veneziano mechanism to explain the U ( 1 ) A problem. We also compare with results obtained by other approaches, especially in the large- N limit, where the issue has been also addressed using, for example, the AdS/CFT correspondence. We discuss issues related to θ dependence in full QCD: the neutron electric dipole moment, the dependence of the topological susceptibility on the quark masses, the U ( 1 ) A symmetry breaking at finite temperature. We also review results in the 2D C P N − 1 model, which is an interesting theoretical laboratory to study issues related to topology. Finally, we discuss the main features of the two-point correlation function of the topological charge density.