Related papers: Super-Penrose process due to collisions inside erg…
In this work we present a new view on the thermodynamics of black holes introducing effects of irreversibility by employing thermodynamic optimization and finite-time thermodynamics. These questions are of importance both in physics and in…
Recently, Banados, Silk and West analyzed a collision of two particles near the horizon of the extremal Kerr black hole and demonstrated that the energy in the center-of-mass frame can be arbitrarily large provided the angular momentum of…
Black holes have sometimes been described as astrophysical particle accelerators because finite energy particles can collide near the horizon with divergent center-of-mass (CM) energy. The collisions are classified by the radial motion of…
Recently, Ban\~{a}dos, Silk and West (BSW) found that the center-of-mass energy of two colliding test particles in the neighborhood of an extreme Kerr black hole could be arbitrarily high when one particle has the critical angular momentum…
We consider collision of two geodesic particles moving around rotating stationary axially symmetric black holes. It is shown for arbitrary nonequatorial motion that under certain conditions the energy in their centre of mass frame can grow…
We first study the escape probability of the spinning particle emitted from the Kerr black hole and find that the escape probability increases with the spin of the particle around the extreme Kerr black hole; in contrast, the escape…
The classical Penrose inequality, a relation between the ADM mass and the area of any cross section of the black hole event horizon, was introduced as a test of the weak cosmic censorship conjecture: if it fails, the trapped surface is not…
We consider near-horizon collisions between two particles moving freely in the Schwarzschild metric in the region outside the horizon. One of them emerges from a white hole. We scrutiny when such a process can lead to the indefinitely large…
Relying on the Penrose process mechanism, we study the possibility of energy extraction from a binary system composed of two extreme electrostatic black holes (BHs) oppositely charged, separated by a strut described by Bonnor's metric (BM).…
A new feature of the rotating black holes is the existence in their ergosphere of trajectories of particles with negative and zero energies. Here we analyze general properties of such trajectories comparing them with usual trajectories of…
A new simple and general explanation of the effect of acceleration of particles by black holes to infinite energies in the centre of mass frame is suggested. It is based on kinematics of particles moving near the horizon. This effect arises…
There are different versions of collisions of two particles near black holes with unbound energy $E_{c.m.}$ in the centre of mass frame. The so-called BSW effect arises when a slow fine-tuned "critical" particle hits a rapid "usual" one. We…
It is known that the center-of-mass energy of the collision of two massive particles following geodesics around a black hole presents a maximum. The maximum energy increases when the black hole is endowed with spin, and for a maximally…
Black holes in Lorentz-violating theories have been claimed to violate the second law of thermodynamics by perpetual motion energy extraction. We revisit this question for a Penrose splitting process in a spherically symmetric setting with…
We study the collision property of spinning particles near a Ba\~nados-Teitelboim-Zanelli (BTZ) black hole. Our results show that although the center-of-mass energy of two ingoing particles diverges if one of the particles possesses a…
In this paper, we study the electric Penrose energy extraction for charged particles in the spacetime of a covariant quantum-corrected Reissner-Nordstr\"om black hole. We first derive the equations of motion and effective potential for…
In recent years, it was found that the energy $E_{c.m.}$ in the centre of mass frame of two colliding particles can be unbounded near black holes. If collision occurs exactly on the horizon, $E_{c.m.}$ is formally infinite. However, in any…
If two particles moving towards a black hole collide near the horizon, their energy in the centre of mass frame can grow unbounded. This is the so-called Banados - Silk - West (BSW) effect. Earlier, it was shown that in the 3+1 space-time…
By employing the new ultraspinning limit we construct novel classes of black holes with non-compact event horizons and finite horizon area and study their thermodynamics. Our ultraspinning limit can be understood as a simple generating…
In the case involving particles the necessary and sufficient condition for the Penrose process to extract energy from a rotating black hole is absorption of particles with negative energies and angular momenta. No torque at the black-hole…