The electromagnetic field effects in in-out and in-in formalisms
The electromagnetic field effects in in-out and in-in formalisms
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DOI：
10.1016/j.physletb.2020.135477
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发表时间：
2020-05
期刊：
影响因子：
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通讯作者：
G. Cao
中科院分区：
文献类型：
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作者：
G. Cao
在这项工作中，我们比较了电磁场对两种形式的强耦合系统的影响：输入-输出和输入-输入，当存在有限电场时，这两种形式是不同的。本文采用手征有效Nambu-Jona-Lasinio模型，考虑了两种电磁场分布：纯电场和等电磁场分量的平行电磁场。对于这两种分布，我们发现当电场(QE)1/2大于手征有效质量M=[m2+(π0)2]1/2时，即当Schwinger对产生机制变得重要时，In-Out和In-In形式的结果开始发散。此外，在In-In形式中，手性修复更具刚性，特别是对于PEM场，其跃迁到一阶而不是二阶。对中性集体模也进行了相应的探索：对于PEM场，由于宇称混合，更精确的计算显示了其极点质量的非单调特征，然后发现由于手征反常，类Goldstone模在手征旋转结束时是无效的。
In this work, we compare the effects of electromagnetic (EM) fields on strong coupling systems in two formalisms: in-out and in-in, which are different from each other when a finite electric field is present. The chiral effective Nambu–Jona-Lasinio model is adopted for this study, and two kinds of EM field distributions are considered: pure electric field and parallel EM (PEM) field with equal electric and magnetic components. For both distributions, we find that the results of in-out and in-in formalisms start to diverge when the electric field (q E) 1/2 is larger than the chiral effective mass M=[m 2+(π 0) 2] 1/2, that is, when the Schwinger pair production mechanism becomes important. Besides, the chiral restorations are stiffer in the in-in formalism, especially the transition shifts to first-order instead of the second-order for the PEM field. The neutral collective modes are also explored accordingly: For the PEM field, more precise calculations show nonmonotonic features of their pole masses due to parity mixing, and then the Goldstone-like mode is found to be noneffective at the end of chiral rotation because of chiral anomaly.