The electromagnetic field effects in in-out and in-in formalisms
Abstract
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 (qE) 1 / 2 is larger than the chiral effective mass M =[m2 +(π0)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.
- Publication:
-
Physics Letters B
- Pub Date:
- July 2020
- DOI:
- 10.1016/j.physletb.2020.135477
- arXiv:
- arXiv:1912.11971
- Bibcode:
- 2020PhLB..80635477C
- Keywords:
-
- Nuclear Theory
- E-Print:
- doi:10.1016/j.physletb.2020.135477