Horizon structure of rotating Bardeen black hole and particle acceleration

Abstract

We investigate the horizon structure and ergosphere in a rotating Bardeen regular black hole, which has an additional parameter (g) due to the magnetic charge, apart from the mass (M) and the rotation parameter (a). Interestingly, for each value of the parameter g, there exists a critical rotation parameter (a = a E ), which corresponds to an extremal black hole with degenerate horizons, while for a < a E it describes a non-extremal black hole with two horizons, and no black hole for a > a E . We find that the extremal value a E is also influenced by the parameter g, and so is the ergosphere. While the value of a E remarkably decreases when compared with the Kerr black hole, the ergosphere becomes thicker with the increase in g. We also study the collision of two equal mass particles near the horizon of this black hole, and explicitly show the effect of the parameter g. The center-of-mass energy (E CM ) not only depend on the rotation parameter a, but also on the parameter g. It is demonstrated that the E CM could be arbitrarily high in the extremal cases when one of the colliding particles has a critical angular momentum, thereby suggesting that the rotating Bardeen regular black hole can act as a particle accelerator.

Generic rotating regular black holes in general relativity coupled to nonlinear electrodynamics

“…In the case of the rotating regular black holes (M = 0), existence of the horizons is strongly dependent on the charge parameter. As in the case of the rotating Hayward [24], Bardeen [62] and ABG [22] non-singular spacetimes, in the case of the current rotating regular black holes, there are the upper limits on the values of the specific charge and rotation parameters in order for the spacetimes to represent black holes. Let us denote these limiting values as a critical values, q cr and a cr , which correspond to the border of the black hole (shaded) and no-horizon (white) regions in top panel of Fig.…”

Non-singular rotating black hole with a time delay in the center

“…The effect is stronger at the equator, and deforms the typical number-eight shape of the inner surface into an hour-glass shape. A similar deformation occurs with the rotating Bardeen black hole [32]. This has the consequence that the same Killing vector is time-like outside the outer stationary limit surfaces and inside the inner one, a fact that will play a important role later on.…”

“…In this paper we restrict attention to the Hayward case. For more details on the rotating Bardeen hole see [32]. Our main intent is to introduce in the metric a nontrivial time delay in the center, as already proposed for the non-rotating case in [20], and further studied in [37].…”

Collision of two general particles around a rotating regular Hayward’s black holes

“…Now, solving Eqs. (9) and (10) simultaneously, and using the condition (12), we obtain the geodesic equations [31,32,37,38] …”

“…It turns out that for these black holes, for each nonzero g, there exists a critical a E , which corresponds to a regular extremal black hole with degenerate horizons [30]. The BSW mechanism for these rotating regular black holes has also been analyzed in [31][32][33], suggesting that a rotating regular black hole can also act as a particle accelerator, which in turn provides a suitable framework for Planck-scale physics.…”