scholarly journals Super-Penrose process due to collisions inside ergosphere

2017 ◽  
Vol 26 (02) ◽  
pp. 1750009
Author(s):  
O. B. Zaslavskii
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Center Of Mass ◽  
Black Hole Horizon ◽  
Mass Frame ◽  
Penrose Process

If two particles collide inside the ergosphere, the energy in the center of mass frame can be made unbound provided at least one of particles has a large negative angular momentum [A. A. Grib and Yu. V. Pavlov, Europhys. Lett. 101 (2013) 20004]. We show that the same condition can give rise to unbounded Killing energy of debris at infinity, i.e. super-Penrose process. Proximity of the point of collision to the black hole horizon is not required.

ACCELERATION OF PARTICLES AS A UNIVERSAL PROPERTY OF ERGOSPHERE

2013 ◽  
Vol 28 (11) ◽  
pp. 1350037 ◽  
Author(s):  
O. B. ZASLAVSKII
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Recent Observation ◽  
Center Of Mass ◽  
Kerr Black Hole ◽  
Acceleration Of Particles ◽  
Axially Symmetric ◽  
Fixed Energy ◽  
Mass Frame

We show that recent observation made by Grib and Pavlov, [A. A. Grib and Yu. V. Pavlov, Europhys. Lett.101, 20004 (2013)] for the Kerr black hole is valid in the general case of rotating axially symmetric metric. Namely, collision of two particles in the ergosphere leads to indefinite growth of the energy in the center-of-mass frame, provided the angular momentum of one of the two particles is negative and increases without limit for a fixed energy at infinity. General approach enabled us to elucidate why the role of the ergosphere is crucial in this process.

scholarly journals Ultrahigh energy particle collisions near the black hole horizon in the strong magnetic field

2014 ◽  
Vol 29 (21) ◽  
pp. 1450112 ◽  
Author(s):  
O. B. Zaslavskii
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Strong Magnetic Field ◽  
Center Of Mass ◽  
Black Hole Horizon ◽  
Ultrahigh Energy ◽  
Particle Collisions ◽  
Energy Particle ◽  
Neutral Particles ◽  
Mass Frame

We consider collision between two charged (or charged and neutral) particles near the black hole horizon in the strong magnetic field B. It is shown that there exists a strip near the horizon within which collision of any two such particles leads to ultrahigh energy in the center-of-mass frame (CM frame). The results apply to generic (not necessarily vacuum) black holes.

scholarly journals ACCELERATION OF PARTICLES BY QUASIBLACK HOLES

2013 ◽  
Vol 22 (06) ◽  
pp. 1350028 ◽  
Author(s):  
O. B. ZASLAVSKII
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Electric Charge ◽  
Center Of Mass ◽  
Finite Energy ◽  
Fine Tuning ◽  
Black Hole Horizon ◽  
Acceleration Of Particles ◽  
Bsw Effect

If two particles collide near the black hole horizon, the energy in their center of mass (CM) frame can grow indefinitely (the so-called Bañados, Silk and West (BSW) effect). This requires fine-tuning the parameters (the energy–momentum, angular momentum or electric charge) of one particle. We show that the CM energy can be unbound also for collisions in the spacetime of quasiblack holes (QBHs) (the objects on the threshold of forming the horizon which do not collapse). It does not require special fine-tuning of parameters and occurs when any particle inside a QBH having a finite energy collides with the particle that entered a QBH from the outside region.

COLLISION ENERGY IN THE CENTER-OF-MASS FRAME FOR ROTATING AND ACCELERATING BLACK HOLES

2012 ◽  
Vol 27 (03) ◽  
pp. 1250017 ◽  
Author(s):  
IBRAR HUSSAIN
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Collision Energy ◽  
Center Of Mass ◽  
The Other ◽  
Extremal Case ◽  
Mass Frame ◽  
Critical Angular Momentum ◽  
Proper Angular Momentum

The center-of-mass (CM) energy of collision for two uncharged particles falling freely from rest at infinity is investigated in the background of charged, rotating and accelerating black hole. It is found that the CM energy of collision is unlimited at the acceleration horizon and at the event horizon (in the extremal case) if one of the colliding particles has critical angular momentum and the other one has a proper angular momentum such that the particle can reach the horizon.

scholarly journals Infrared effects in the late stages of black hole evaporation

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Éanna É. Flanagan
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Center Of Mass ◽  
Planck Scale ◽  
Black Hole Mass ◽  
Order Unity ◽  
Intrinsic Angular Momentum ◽  
Hole Position ◽  
Late Stages ◽  
Shear Tensor

Abstract As a black hole evaporates, each outgoing Hawking quantum carries away some of the black holes asymptotic charges associated with the extended Bondi-Metzner-Sachs group. These include the Poincaré charges of energy, linear momentum, intrinsic angular momentum, and orbital angular momentum or center-of-mass charge, as well as extensions of these quantities associated with supertranslations and super-Lorentz transformations, namely supermomentum, superspin and super center-of-mass charges (also known as soft hair). Since each emitted quantum has fluctuations that are of order unity, fluctuations in the black hole’s charges grow over the course of the evaporation. We estimate the scale of these fluctuations using a simple model. The results are, in Planck units: (i) The black hole position has a uncertainty of $$ \sim {M}_i^2 $$ ∼ M i 2 at late times, where Mi is the initial mass (previously found by Page). (ii) The black hole mass M has an uncertainty of order the mass M itself at the epoch when M ∼ $$ {M}_i^{2/3} $$ M i 2 / 3 , well before the Planck scale is reached. Correspondingly, the time at which the evaporation ends has an uncertainty of order $$ \sim {M}_i^2 $$ ∼ M i 2 . (iii) The supermomentum and superspin charges are not independent but are determined from the Poincaré charges and the super center-of-mass charges. (iv) The supertranslation that characterizes the super center-of-mass charges has fluctuations at multipole orders l of order unity that are of order unity in Planck units. At large l, there is a power law spectrum of fluctuations that extends up to l ∼ $$ {M}_i^2/M $$ M i 2 / M , beyond which the fluctuations fall off exponentially, with corresponding total rms shear tensor fluctuations ∼ MiM−3/2.

THE STEREODYNAMICS STUDY OF THE C(3P) + OH (X2 Π) → CO(X1Σ+) + H(2S) REACTION

2010 ◽  
Vol 09 (05) ◽  
pp. 935-943 ◽  
Author(s):  
PENG SONG ◽  
YONG-HUA ZHU ◽  
JIAN-YONG LIU ◽  
FENG-CAI MA
Keyword(s):  
Angular Momentum ◽  
Cross Sections ◽  
Collision Energy ◽  
Energy Surface ◽  
Center Of Mass ◽  
Title Reaction ◽  
High Collision Energy ◽  
Dependency Relationship ◽  
Energy Dependency ◽  
Mass Frame

The stereodynamics of the title reaction on the ground electronic state X2A' potential energy surface (PES)1 has been studied using the quasiclassical trajectory (QCT) method. The commonly used polarization-dependent differential cross-sections (PDDCSs) of the product and the angular momentum alignment distribution, P(θr) and P(Φr), are generated in the center-of-mass frame using QCT method to gain insight of the alignment and orientation of the product molecules. Influence of collision energy on the stereodynamics is shown and discussed. The results reveal that the distribution of P(θr) and P(Φr) is sensitive to collision energy. The PDDCSs exhibit different collision energy dependency relationship at low and high collision energy ranges.

Super-Penrose process

2020 ◽  
Vol 35 (02n03) ◽  
pp. 2040058
Author(s):  
O. B. Zaslavskii
Keyword(s):  
Black Hole ◽  
Flat Space ◽  
Space Time ◽  
Centre Of Mass ◽  
Rotating Black Hole ◽  
Mass Frame ◽  
Penrose Process ◽  
Energy Formula ◽  
Full Classification

If two particles collide near a rotating black hole, their energy in the centre of mass frame can become unbounded under certain conditions. In doing so, the Killing energy [Formula: see text] of debris at infinity is, in general, remain restricted. If [Formula: see text] is also unbounded, this is called the super-Penrose process. We elucidate when such a process is possible and give full classification of corresponding relativistic objects for rotating space-times. We also discuss the case of a pure electric super-Penrose process that is valid even in the flat space-time. The key role in consideration is played by the Wald inequalities.

scholarly journals High-energy collision of particles in the magnetic field far from black holes

2014 ◽  
Vol 29 (29) ◽  
pp. 1450151
Author(s):  
O. B. Zaslavskii
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Center Of Mass ◽  
High Energy ◽  
Axially Symmetric ◽  
High Energy Collision ◽  
Mass Frame ◽  
Symmetric Black Hole ◽  
Rotating Star ◽  
The Magnetic Field

We consider collision of two particles in the axially symmetric black hole metric in the magnetic field. If the value of the angular momentum |L| of one particles grows unbound (but its Killing energy remains fixed) one can achieve unbound energy in the center-of-mass frame E c.m. In the absence of the magnetic field, collision of this kind is known to happen in the ergoregion. However, if the magnetic field strength B is also large, with the ratio |L|/B being finite, large E c.m. can be achieved even far from a black hole, in the almost flat region. Such an effect also occurs in the metric of a rotating star.

From Schwarzschild to Kerr under de Sitter background due to blackhole tunnelling

2007 ◽  
Vol 85 (8) ◽  
pp. 863-868 ◽  
Author(s):  
K Xiao ◽  
W Liu
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Event Horizon ◽  
Hawking Radiation ◽  
Emission Rate ◽  
Momentum Conservation ◽  
Black Hole Horizon ◽  
De Sitter ◽  
Quantum Tunnelling ◽  
Sitter Background

When a particle with angular momentum tunnels across the event horizon of Schwarzschild–de Sitter black hole, the black hole will change into a Kerr–de Sitter one. Considering Hawking radiation as a process of quantum tunnelling near a black-hole horizon, the emission rate of the particles with angular momentum is calculated under energy and angular momentum conservation, and the result is consistent with an underlying unitary theory.PACS Nos.: 97.60.Lf, 04.70.Dy, 03.65.Pm

scholarly journals High-energy collisions inside black holes and their counterpart in flat spacetime

2014 ◽  
Vol 23 (05) ◽  
pp. 1450045 ◽  
Author(s):  
O. B. Zaslavskii
Keyword(s):  
Black Hole ◽  
Center Of Mass ◽  
High Energy ◽  
General Character ◽  
Particle Collisions ◽  
Flat Spacetime ◽  
Mass Frame ◽  
High Energy Collisions ◽  
Horizon Geometry

Two particles can collide inside a nonextremal black hole in such a way that the energy E c.m. in their center-of-mass frame becomes as large as one likes. We show that this effect can be understood with the help of a simple analogy with particle collisions in flat spacetime. As the two-dimensional part of near-horizon geometry inside a black hole is described by the flat Milne metric, the results have a general character. Full classification of scenarios with unbound E c.m. is suggested. Some scenarios of this kind require proximity of collision to the bifurcation point, but for some other ones this is not necessary.

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