Papers by Kausari Sultana
Rotation induced break down of Weak Equivalence Principle in Schwarzschild?(Anti-) de Sitter Geometry
Romanian Astronomical Journal, Oct 1, 2017
Tunneling of Charged and Magnetized Fermions from a Rotating Dyonic Taub-NUT Black Hole
RoAJ, Dec 1, 2017
Charged Dirac Particles’ Hawking Radiation via Tunneling of Both Horizons and Thermodynamics Properties of Kerr–Newman–Kasuya–Taub–NUT–AdS Black Holes
International Journal of Theoretical Physics, 2013
ABSTRACT We investigate Hawking radiation of electrically and magnetically charged Dirac particle... more ABSTRACT We investigate Hawking radiation of electrically and magnetically charged Dirac particles from a dyonic Kerr-Newman-Kasuya-Taub-NUT-Anti-de Sitter (KNKTN-AdS) black hole by considering thermal characters of both the outer and inner horizons. We apply Damour-Ruffini method and membrane method to calculate the temperature and the entropy of the inner horizon of the KNKTN-AdS black hole. The inner horizon admits thermal character with positive temperature and entropy proportional to its area. The inner horizon entropy contributes to the total entropy of the black hole in the context of Nernst theorem. Considering conservation of energy, charges, angular momentum, and the back-reaction of emitting particles to the spacetime, we obtain the emission spectra for both the inner and outer horizons. The total emission rate is obtained as the product of the emission rates of the inner and outer horizons. It deviates from the purely thermal spectrum with the leading term exactly the Boltzman factor and can bring some information out. The result thus can be treated as an explanation to the information loss paradox.
International Journal of Theoretical Physics, 2014
We investigate Hawking radiation of charged and magnetized (scalar /fermion) particles from Demia... more We investigate Hawking radiation of charged and magnetized (scalar /fermion) particles from Demiański-Newman (DN) black holes using Hamilton-Jacobi (HJ) ansatz. Taking into account conservation of energy and the backreaction of particles to the spacetime, we calculate the emission rate and find it proportional to the change of Bekenstein-Hawking entropy. The radiation spectrum deviates from the precisely thermal one and is accordant with that obtained by the null geodesic method, but its physical picture is more clear. The investigation specifies a quantum-corrected radiation temperature dependent on the black hole background and the radiation particle's energy, angular momentum, and charges.
Reissner-Nordstrom Metric Violates Weak Equivalence Principle by Rotation
GANIT: Journal of Bangladesh Mathematical Society
Blood flow through arterial stenosis can play a crucial role at the post stenotic flow regions. T... more Blood flow through arterial stenosis can play a crucial role at the post stenotic flow regions. This produces a disturbance in the normal flow path. The intensity of the flow disturbance (i.e. laminar, transitional and turbulent flow characteristics) depends not only on the severity of the stenosis but also on the pattern of the geometrical model. In that case, the turbulence model plays vital role to measure these flow disturbances. However, it is very important to choose a proper flow simulation model that can predict the flow behavior of fluid accurately and efficiently with less computational cost and time. Thus, this study aims to analyze the results of two turbulence models i.e. k-ω and k-ε for blood flow simulation to compare their performance for the prediction of the flow behavior. Simulations have been performed with 75% area reductions in the arteries. The results of simulation show that, the flow parameters obtained from the k-ε model exhibits lack of fits with the exper...
Particles’ Tunneling from Cosmic String Black Holes surrounded by Quintessence
International Journal of Theoretical Physics
Tunneling of Charged Massive Particles from Taub-NUT-Reissner-Nordström-AdS Black Holes
International Journal of Theoretical Physics, 2014
ABSTRACT We apply the null-geodesic method to investigate tunneling radiation of charged and magn... more ABSTRACT We apply the null-geodesic method to investigate tunneling radiation of charged and magnetized massive particles from Taub-NUT-Reissner-Nordström black holes endowed with electric as well as magnetic charges in Anti-de Sitter (AdS) spaces. The geodesics of charged massive particle tunneling from the black hole is not lightlike, but can be determined by the phase velocity. We find that the tunneling rate is related to the difference of Bekenstein-Hawking entropies of the black hole before and after the emission of particles. The entropy differs from just a quarter area at the horizon of black holes with NUT parameter. The emission spectrum is not precisely thermal anymore and the deviation from the precisely thermal spectrum can bring some information out, which can be treated as an explanation to the information loss paradox. The result can also be treated as a quantum-corrected radiation temperature, which is dependent on the black hole background and the radiation particle’s energy and charges.
Charged Particles’ Hawking Radiation via Tunneling of Both Horizons from Reissner-Nordström-Taub-NUT Black Holes
International Journal of Theoretical Physics, 2013
Abstract In some recent derivations thermal characters of the inner horizon have been employed; h... more Abstract In some recent derivations thermal characters of the inner horizon have been employed; however, the understanding of possible role that may play the inner horizons of black holes in black hole thermodynamics is still somewhat incomplete. Motivated by this problem we investigate Hawking radiation of the Reissner-Nordström-Taub-NUT (RNTN) black hole by considering thermal characters of both the outer and inner horizons. We apply Damour-Ruffini method and the thin film brick wall model to calculate the temperature and the entropy of the inner horizon of the RNTN black hole. The inner horizon admits thermal character with positive temperature and entropy proportional to its area, and it thus may contribute to the total entropy of the black hole in the context of Nernst theorem. Considering conservations of energy and charge and the back-reaction of emitting particles to the spacetime, the emission spectra are obtained for both the inner and outer horizons. The total emission rate is the product of the emission rates of the inner and outer horizons, and it deviates from the purely thermal spectrum and can bring some information out. Thus, the result can be treated as an explanation to the information loss paradox. Keywords Hawking radiation · Damour-Ruffini method · Back-reaction · Entropy · Inner horizon · Bekenstein-Smarr formula
International Journal of Theoretical Physics DOI 10.1007/s10773-014-2154-1, May 6, 2014
Abstract We investigate Hawking radiation of charged and magnetized (scalar /fermion)
particles ... more Abstract We investigate Hawking radiation of charged and magnetized (scalar /fermion)
particles from Demia´nski-Newman (DN) black holes using Hamilton-Jacobi (HJ) ansatz.
Taking into account conservation of energy and the backreaction of particles to the spacetime,
we calculate the emission rate and find it proportional to the change of Bekenstein-
Hawking entropy. The radiation spectrum deviates from the precisely thermal one and is
accordant with that obtained by the null geodesic method, but its physical picture is more
clear. The investigation specifies a quantum-corrected radiation temperature dependent on
the black hole background and the radiation particle’s energy, angular momentum, and
charges.
International Journal of Theoretical Physics 53 (2013) 1441–1453; DOI 10.1007/s10773-013-1942-3
Abstract We apply the null-geodesic method to investigate tunneling radiation of charged and magn... more Abstract We apply the null-geodesic method to investigate tunneling radiation of charged and magnetized massive particles from Taub-NUT-Reissner-Nordström black holes endowed with electric as well as magnetic charges in Anti-de Sitter (AdS) paces. The geodesics of charged massive particle tunneling from the black hole is not lightlike, but can be determined by the phase velocity. We find that the tunneling rate is related to the difference
of Bekenstein-Hawking entropies of the black hole before and after the emission of particles. The entropy differs from just a quarter area at the horizon of black holes with NUT parameter. The emission spectrum is not precisely thermal anymore and the deviation from the precisely thermal spectrum can bring some information out, which can be treated as an explanation to the information loss paradox. The result can also be treated as a quantumcorrected radiation temperature, which is dependent on the black hole background and the radiation particle’s energy and charges.
Keywords Semi-classical tunneling · Charged and magnetized particle · Backreaction · Bekenstein-Hawking entropy
International Journal of Theoretical Physics 52 (2013) 4537–4556; DOI 10.1007/s10773-013-1772-3
Abstract We investigate Hawking radiation of electrically and magnetically charged Dirac
particl... more Abstract We investigate Hawking radiation of electrically and magnetically charged Dirac
particles from a dyonic Kerr–Newman–Kasuya–Taub–NUT–Anti-de Sitter (KNKTN–AdS)
black hole by considering thermal characters of both the outer and inner horizons.We apply
Damour–Ruffini method and membrane method to calculate the temperature and the entropy
of the inner horizon of the KNKTN–AdS black hole. The inner horizon admits thermal
character with positive temperature and entropy proportional to its area. The inner horizon
entropy contributes to the total entropy of the black hole in the context of Nernst theorem.
Considering conservation of energy, charges, angular momentum, and the back-reaction of
emitting particles to the spacetime, we obtain the emission spectra for both the inner and
outer horizons. The total emission rate is obtained as the product of the emission rates of
the inner and outer horizons. It deviates from the purely thermal spectrum with the leading
term exactly the Boltzman factor and can bring some information out. The result thus can
be treated as an explanation to the information loss paradox.
Keywords Inner horizon · Tunneling · Back-reaction · Entropy · Nerst theorem ·
Bekenstein–Smarr formula
Int J Theor Phys (2013) 52:2802–2817; DOI 10.1007/s10773-013-1572-9
Abstract In some recent derivations thermal characters of the inner horizon have been employed;
... more Abstract In some recent derivations thermal characters of the inner horizon have been employed;
however, the understanding of possible role that may play the inner horizons of
black holes in black hole thermodynamics is still somewhat incomplete. Motivated by this
problem we investigate Hawking radiation of the Reissner-Nordström-Taub-NUT (RNTN)
black hole by considering thermal characters of both the outer and inner horizons. We apply
Damour-Ruffini method and the thin film brick wall model to calculate the temperature
and the entropy of the inner horizon of the RNTN black hole. The inner horizon admits
thermal character with positive temperature and entropy proportional to its area, and it thus
may contribute to the total entropy of the black hole in the context of Nernst theorem. Considering
conservations of energy and charge and the back-reaction of emitting particles to
the spacetime, the emission spectra are obtained for both the inner and outer horizons. The
total emission rate is the product of the emission rates of the inner and outer horizons, and
it deviates from the purely thermal spectrum and can bring some information out. Thus, the
result can be treated as an explanation to the information loss paradox.
Keywords Hawking radiation · Damour-Ruffini method · Back-reaction · Entropy · Inner
horizon · Bekenstein-Smarr formula
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Papers by Kausari Sultana
particles from Demia´nski-Newman (DN) black holes using Hamilton-Jacobi (HJ) ansatz.
Taking into account conservation of energy and the backreaction of particles to the spacetime,
we calculate the emission rate and find it proportional to the change of Bekenstein-
Hawking entropy. The radiation spectrum deviates from the precisely thermal one and is
accordant with that obtained by the null geodesic method, but its physical picture is more
clear. The investigation specifies a quantum-corrected radiation temperature dependent on
the black hole background and the radiation particle’s energy, angular momentum, and
charges.
of Bekenstein-Hawking entropies of the black hole before and after the emission of particles. The entropy differs from just a quarter area at the horizon of black holes with NUT parameter. The emission spectrum is not precisely thermal anymore and the deviation from the precisely thermal spectrum can bring some information out, which can be treated as an explanation to the information loss paradox. The result can also be treated as a quantumcorrected radiation temperature, which is dependent on the black hole background and the radiation particle’s energy and charges.
Keywords Semi-classical tunneling · Charged and magnetized particle · Backreaction · Bekenstein-Hawking entropy
particles from a dyonic Kerr–Newman–Kasuya–Taub–NUT–Anti-de Sitter (KNKTN–AdS)
black hole by considering thermal characters of both the outer and inner horizons.We apply
Damour–Ruffini method and membrane method to calculate the temperature and the entropy
of the inner horizon of the KNKTN–AdS black hole. The inner horizon admits thermal
character with positive temperature and entropy proportional to its area. The inner horizon
entropy contributes to the total entropy of the black hole in the context of Nernst theorem.
Considering conservation of energy, charges, angular momentum, and the back-reaction of
emitting particles to the spacetime, we obtain the emission spectra for both the inner and
outer horizons. The total emission rate is obtained as the product of the emission rates of
the inner and outer horizons. It deviates from the purely thermal spectrum with the leading
term exactly the Boltzman factor and can bring some information out. The result thus can
be treated as an explanation to the information loss paradox.
Keywords Inner horizon · Tunneling · Back-reaction · Entropy · Nerst theorem ·
Bekenstein–Smarr formula
however, the understanding of possible role that may play the inner horizons of
black holes in black hole thermodynamics is still somewhat incomplete. Motivated by this
problem we investigate Hawking radiation of the Reissner-Nordström-Taub-NUT (RNTN)
black hole by considering thermal characters of both the outer and inner horizons. We apply
Damour-Ruffini method and the thin film brick wall model to calculate the temperature
and the entropy of the inner horizon of the RNTN black hole. The inner horizon admits
thermal character with positive temperature and entropy proportional to its area, and it thus
may contribute to the total entropy of the black hole in the context of Nernst theorem. Considering
conservations of energy and charge and the back-reaction of emitting particles to
the spacetime, the emission spectra are obtained for both the inner and outer horizons. The
total emission rate is the product of the emission rates of the inner and outer horizons, and
it deviates from the purely thermal spectrum and can bring some information out. Thus, the
result can be treated as an explanation to the information loss paradox.
Keywords Hawking radiation · Damour-Ruffini method · Back-reaction · Entropy · Inner
horizon · Bekenstein-Smarr formula