The spontaneous pair production of charged scalars in a near extremal Kerr-Newman (KN) black hole is analytically studied. It is shown that the existence condition for the pair production is equivalent to the violation of the Breitenlohner-Freedman bound in an AdS2 space. The mean number of produced pairs in the extremal black hole has a thermal interpretation, in which the effective temperature for the Schwinger effect in the AdS2 space persistently holds, while the mean number in the near extremal black hole has an additional factor of the Schwinger effect in the Rindler space. In addition, the holographic dual conformal field theory (CFT) descriptions of the charged scalar pair production are respectively realized both in the J and Q pictures in terms of the KN/CFTs correspondence.

We study the spontaneous pair production of scalar dyons in the near extremal dyonic Kerr-Newman (KN) black hole, which contains a warped AdS3 structure in the near horizon region. The leading term contribution of the pair production rate and the absorption cross section ratio are also calculated using the Hamilton-Jacobi approach and the thermal interpretation is given. In addition, the holographic dual conformal field theories (CFTs) descriptions of the pair production rate and absorption cross section ratios are analyzed both in the J-, Q-and P -pictures respectively based on the threefold dyonic KN/CFTs dualities. PACS numbers: 04.62.+v, 04.70.Dy, 12.20.-m I. INTRODUCTIONThe spontaneous pair production is associated with the separation of the virtual particle pairs, which can be caused by an external electromagnetic force or by the tunnelling through a causal boundary. These effects are related with two independent quantum processes: the Schwinger mechanism [1] and the Hawking radiation [2]. A charged black hole can provide a suitable arena to address both processes. Moreover, it is shown that the leading contribution of the Schwinger effect comes from the dominating electromagnetic field in the near horizon region of the charged black hole and the pair production rate is shown to match with that obtained in the whole black hole background [3][4][5][6]. Besides, for the near extremal charged black holes, the symmetry of the near horizon geometry is enhanced, e.g. AdS 2 × S 2 for the Reissner-Nordström (RN), and a warped AdS 3 = AdS 2 × S 1 for the Kerr-Newman (KN) black hole, which leads to a holographic dual conformal field theory (CFT) description of the black holes [7][8][9][10][11][12][13][14][15].Recently, the pair production of scalar field [3] and spinor field [4] in the near horizon region of RN black holes, as well as pair production of scalar field in near extremal KN black holes [6] have been systematically analyzed. An interesting finding was that the violation of the Breitenlohner-Freedman (BF) bound in the AdS 2 or the warped AdS 3 geometry is equivalent to the existence condition for the pair production, and also guarantees the cosmic censorship conjecture during the pair production process. This condition, viewed in the AdS/CFT correspondence, results in the "complex" conformal dimensions of operators in the dual CFT, which indicates the dual (super)gravity solution is unstable [16]. More interestingly, the pair production from the near extremal RN or KN black holes exhibit a thermal interpretation [6,17,18], in which the production rate depends on an effective temperature coming from a combination of the Unruh temperature caused by the acceleration driven by the electromagnetic force and the AdS curvature [19]. Moreover, the particle mass is modified by the AdS curvature and the quantum number of the compact space, which reduces the Schwinger effect in AdS 2 [6,17,19]. This effect is analogous to the transverse momentum of particle spectrum produced by an electric field in quantum electrodyna...

Abstract. The pair production of charged scalar dyons is analytically studied in nearextremal Kerr-Newman (KN) dyonic black holes. The pair production rate and its thermal interpretation are given. Moreover, the absorption cross section ratio has been compared with the two-point function of the conformal field theories (CFTs) holographically dual to the near horizon geometry, namely warped AdS 3 , of the near extremal Kerr-Newman black holes to verify the threefold dyonic KN/CFTs correspondence.