Ashfaque Bokhari

Prof. Dr. Ashfaque Bokhari

Department of Mathematics and Statistics, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
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Research Focus & Metrics

Academic Career Length

42Years (1985-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 October 2010 in Nonlinear Analysis: Real World Applications
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ABAshfaque Bokhari
Ashfaque Bokhari
AAAhmad Al-Dweik
Ahmad Al-Dweik
FZFiazuddin Zaman
Fiazuddin Zaman
AKA.H. Kara
A.H. Kara
Fazal MahomedFazal Mahomed
Fazal Mahomed

31 December 2020 in Physical Review D
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ABAshfaque Bokhari
Ashfaque Bokhari
JRJavlon Rayimbaev
Javlon Rayimbaev
Bobomurat AhmedovBobomurat Ahmedov
Bobomurat Ahmedov
In this paper we study the dynamics of neutral, electrically charged and magnetized particles around deformed electrically and magnetically charged Reissner-Nordström black holes. For the neutral test particles motion, it is shown that the radius of the innermost stable circular orbits (ISCOs) decrease with the increase in both the black hole charge and positive spacetime deformation. It reaches up to 3.85M at the value of deformation parameter ε=20.45 in Schwarzschild spacetime case (Q=0). In the extreme charged Reissner–Nordstrom black hole case, the ISCO decreases up to 2.26M at the value of deformation parameter ε=6.17. Moreover, the negative deformation results in an increase in the ISCO radius. Comparing effects of positive deformation and the Reissner-Nordström black hole charge with spin of rotating Kerr black holes, it is shown that the extremely charged Reissner-Nordström black hole can mimic rotating Kerr black hole up to the spin parameter a/M=0.48, while for the positive deformation with ε=6.17 the mimic value increases up to a/M=0.88 implying that the supermassive black hole M87 cannot be considered as Reissner-Nordström black hole. Using this comparison, we estimate charge of the supermassive black hole Sagittarius A* as Q/M≃0.8287 without deformation which can mimic the spin of the black hole. When the deformation ε=1, the mimic charge increases up to Q/M≃0.8926. Our study of the energy extraction from the accretion disk shows that the maximum energy efficiency increases up to 20.02%, which is almost the same for extreme Kerr black hole case (20.6%). We have also considered the behaviour of ISCO of electrically charged particles showing that the attractive (repulsive) electrostatic interactions cause rapid increase (slightly decrease) of the ISCO radius. Finally, we have explored the dynamics of magnetized particles around deformed magnetically charged Reissner-Nordström black hole. By treating the magnetar PSR J1745-2900, orbiting the supermassive black hole Sagittarius A* as a magnetized particle, showing that the magnetic charge of pure Reissner-Nordström black hole can mimic spin of a rotating Kerr black hole up to a/M≃0.82 for the value to be in the range Qm/M∈(0,0.692). Moreover, we find that the positive values of the deformation parameter lead to shift the ISCO for the magnetized particles toward the central object.

3 November 2015 in The European Physical Journal C
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SKSuhail Khan
Suhail Khan
THTahir Hussain
Tahir Hussain
ABAshfaque Bokhari
Ashfaque Bokhari
GKGulzar Ali Khan
Gulzar Ali Khan

1 May 1987 in Journal of Mathematical Physics
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ABAshfaque Bokhari
Ashfaque Bokhari
AQAsghar Qadir
Asghar Qadir
In this paper it is shown that reduction from maximal to minimal static, spherical symmetry of a space-time occurs in only one step reducing the number of independent Killing vector fields from 10 to 4. Maximal symmetry corresponds only to the de Sitter, anti-de Sitter, and Minkowski metrics, without reference to the Einstein field equations.

1 August 1993 in Journal of Mathematical Physics
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ABAshfaque Bokhari
Ashfaque Bokhari
AQAsghar Qadir
Asghar Qadir
Ricci collineations for the Ricci tensor which is constructed from a general spherically symmetric and static metric are classified for all possibilities of Rab(r) (such that Rab≠0 for a=b). It turns out that the only collineations admitted by this tensor can be ten, six, or four and there does not appear any case in between.

10 May 2006 in International Journal of Theoretical Physics
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ABAshfaque Bokhari
Ashfaque Bokhari
AKA. H. Kara
A. H. Kara
AKA. R. Kashif
A. R. Kashif
FZFiazuddin Zaman
Fiazuddin Zaman