Energy extraction and particle acceleration around a rotating dyonic black hole in $N=2$, $U(1)^2$ gauged supergravity (1906.03566v5)

Abstract: In the present paper, we explore various gravitational aspects such as energy extraction (via the Penrose process and Superradiance), particle collisions around a $\mathcal{N}=2$, $U(1)^2$ dyonic rotating black hole (BH) in the gauged supergravity model. The impact of the rotation parameter ($a$) and the gauge coupling constant ($g$) on the behaviour of horizon and ergoregion of the BH is studied. It is of interest to note that, compared with the extremal Kerr BH, the gauge coupling constant, under certain constraints, can enhance the maximum efficiency of energy extraction by the Penrose process almost double. Under the same constraints, we can extract approximately 60.75\% of the initial mass energy from the BH which is noticeably higher in contrast to the extremal Kerr BH. The limit of energy extraction in terms of the local speeds of the fragments is also examined with the help of the Wald inequality. We identify an upper limit on the gauge coupling constant up to which the phenomenon of Superradiance is likely to occur. Finally, we computed the center-of-mass energy ($E_{CM}$) of two particles with the same rest masses moving in the equatorial plane of the BH. Our study also aims to sensitize $E_{CM}$ to the rotation parameter and the gauge coupling constant for extremal and nonextremal spacetime as well. Especially, for the extremal case, an infinitely large amount of $E_{CM}$ can be achieved closer to the horizon which allows the BH to serve as a more powerful Planck-energy-scale collider as compared to Kerr and any other generalized BHs in the Kerr family explored so far in general relativity. However, $E_{CM}$ for the nonextremal spacetime is shown to be finite and has an upper bound.