Pair production of scalars around near-extremal Kerr-Sen black holes

We investigate the charged scalar pair production near the horizon of a near-extremal Kerr-Sen black holes. The condition for pair production to occur has relation to the violation of Breitenlohner-Freedman bound in an AdS$_2$ space. The method employed in this work has been used to show the pair production in the near-horizon of a near-extremal Kerr-Newman black hole and its non-rotating case as well. We also discuss the static limit of our result.Comment: 16 pages, 1 figur

Destroying Kerr-Sen black holes

By neglecting the self-force, self-energy, and radiative effects, it has been shown that an extremal or near-extremal Kerr-Newman black hole can turn into a naked singularity when it captures charged and spinning massive particles. A straightforward question then arises: do charged and rotating black holes in string theory possess the same property? In this paper we apply the Wald's gedanken experiment, in his study on the possibility of destroying extremal Kerr-Newman black holes, to the case of (near-)extremal Kerr-Sen black holes. We find that feeding a test particle into a (near-)extremal Kerr-Sen black hole could lead to a violation of the extremal bound for the black hole.Comment: 10 pages, 3 figures; v2: 13 pages, refs are added, figures are improved, some conclusions are change

Hidden conformal symmetry for the accelerating Kerr black holes

According to Kerr/CFT correspondence, some aspects of extremal and non-extremal Kerr black holes could be explained by using a 2D CFT. This paper is devoted to show how Kerr/CFT correspondence can work for the slowly accelerating Kerr black holes, in both extremal and non-extremal cases. The equation of motion for low frequency scalar probes in the near region possesses the "hidden" conformal symmetry, similar to that of the non-accelerating version. Assuming a particular value of associated central charge, Cardy formula in 2D CFT can recover the Bekenstein-Hawking entropy for the black hole under consideration. Moreover, agreements in the scattering process between gravitational and 2D CFT dual suggest the existence of slowly accelerating Kerr/CFT duality.Comment: 17 pages, no figures; v2: 19 pages, refs added, a new appendix for Kretschmann scala

ANALISIS KELAYAKAN EKSPANSI USAHA INDUSTRI BATAKO PRESS MESIN PADA CV. HAN MAJU JAYA BLOCK DI PERIGI LAMA

ANALISIS KELAYAKAN EKSPANSI USAHA INDUSTRI BATAKO PRESS MESIN PADA CV. HAN MAJU JAYA BLOCK DI PERIGI LAM