1,270 research outputs found
Komar energy and Smarr formula for noncommutative Schwarzschild black hole
We calculate the Komar energy for a noncommutative Schwarzschild black
hole. A deformation from the conventional identity is found in the
next to leading order computation in the noncommutative parameter
(i.e. ) which is also consistent
with the fact that the area law now breaks down. This deformation yields a
nonvanishing Komar energy at the extremal point of these black holes.
We then work out the Smarr formula, clearly elaborating the differences from
the standard result , where the mass () of the black hole is
identified with the asymptotic limit of the Komar energy. Similar conclusions
are also shown to hold for a deSitter--Schwarzschild geometry.Comment: 5 pages Late
Glassy Phase Transition and Stability in Black Holes
Black hole thermodynamics, confined to the semi-classical regime, cannot
address the thermodynamic stability of a black hole in flat space. Here we show
that inclusion of correction beyond the semi-classical approximation makes a
black hole thermodynamically stable. This stability is reached through a phase
transition. By using Ehrenfest's scheme we further prove that this is a glassy
phase transition with a Prigogine-Defay ratio close to 3. This value is well
placed within the desired bound (2 to 5) for a glassy phase transition. Thus
our analysis indicates a very close connection between the phase transition
phenomena of a black hole and glass forming systems. Finally, we discuss the
robustness of our results by considering different normalisations for the
correction term.Comment: v3, minor changes over v2, references added, LaTeX-2e, 18 pages, 3 ps
figures, to appear in Eour. Phys. Jour.
Quantum corrections to the entropy of charged rotating black holes
Hawking radiation from a black hole can be viewed as quantum tunneling of
particles through the event horizon. Using this approach we provide a general
framework for studying corrections to the entropy of black holes beyond
semiclassical approximations. Applying the properties of exact differentials
for three variables to the first law thermodynamics, we study charged rotating
black holes and explicitly work out the corrections to entropy and horizon area
for the Kerr-Newman and charged rotating BTZ black holes. It is shown that the
results for other geometries like the Schwarzschild, Reissner-Nordstr\"{o}m and
anti-de Sitter Schwarzschild spacetimes follow easily
Black Hole Entropy: From Shannon to Bekenstein
In this note we have applied directly the Shannon formula for information
theory entropy to derive the Black Hole (Bekenstein-Hawking) entropy. Our
analysis is semi-classical in nature since we use the (recently proposed [8])
quantum mechanical near horizon mode functions to compute the tunneling
probability that goes in to the Shannon formula, following the general idea of
[5]. Our framework conforms to the information theoretic origin of Black Hole
entropy, as originally proposed by Bekenstein.Comment: 9 pages Latex, Comments are welcome; Thoroughly revised version,
reference and acknowledgements sections enlarged, numerical error in final
result corrected, no major changes, to appear in IJT
Higher order WKB corrections to black hole entropy in brick wall formalism
We calculate the statistical entropy of a quantum field with an arbitrary
spin propagating on the spherical symmetric black hole background by using the
brick wall formalism at higher orders in the WKB approximation. For general
spins, we find that the correction to the standard Bekenstein-Hawking entropy
depends logarithmically on the area of the horizon. Furthermore, we apply this
analysis to the Schwarzschild and Schwarzschild-AdS black holes and discuss our
results.Comment: 21 pages, published versio
Anomaly analysis of Hawking radiation from Kaluza-Klein black hole with squashed horizon
Considering gravitational and gauge anomalies at the horizon, a new method
that to derive Hawking radiations from black holes has been developed by
Wilczek et al. In this paper, we apply this method to non-rotating and rotating
Kaluza-Klein black holes with squashed horizon, respectively. For the rotating
case, we found that, after the dimensional reduction, an effective U(1) gauge
field is generated by an angular isometry. The results show that the gauge
current and energy-momentum tensor fluxes are exactly equivalent to Hawking
radiation from the event horizon.Comment: 15 pages, no figures, the improved version, accepted by Eur. Phys. J.
Thermodynamics Inducing Massive Particles' Tunneling and Cosmic Censorship
By calculating the change of entropy, we prove that the first law of black
hole thermodynamics leads to the tunneling probability of massive particles
through the horizon, including the tunneling probability of massive charged
particles from the Reissner-Nordstr\"om black hole and the Kerr-Newman black
hole. Novelly, we find the trajectories of massive particles are close to that
of massless particles near the horizon, although the trajectories of massive
charged particles may be affected by electromagnetic forces. We show that
Hawking radiation as massive particles tunneling does not lead to violation of
the weak cosmic-censorship conjecture
Sustainable financing for new vaccines in Indonesia: challenges and strategies
Immunization is one of the most cost-effective interventions in global health and has a crucial role in achieving 14 of the 17 sustainable development goals (SDGs). The issue of sustainable financing for new vaccines is particularly pertinent as Indonesia transitions away from extensive Gavi support towards a self-financing immunization system. As the current immunization system transitions, practical solutions must be found and applied to provide more flexibility in the budget for financing immunizations without sacrificing the current healthcare system’s needs. Despite the fact that economic evaluation studies are essential as an initial step to ensure financial readiness, the lack of reliable data is the first barrier to Indonesia’s journey toward a self-financing immunization system. To overcome this problem, standardization of data collection strategies and methodologies are required. In particular, Indonesia may have to explore other options to increase revenue for its immunization system, such as through general revenue from the central government, a sector-wide approach to financing, and a national trust fund. To deal with the tight immunization budget and its consequences, Indonesia also has to restructure its immunization system, which can be implemented through province block grants, insurance mandate and subsidy. Taking the potential of a COVID-19 vaccine into account, the Indonesian government should consider a number of costs and issues beyond the development and procurement of vaccines. The costs of delivering vaccines to the remote parts of Indonesia, implementing the necessary infrastructure, and modifying vaccine delivery are also important in this time of transition. These constraints must be addressed in the new self-financing system and other public health efforts must be increased to decrease the burden of infectious disease as Indonesia develops a stronger immunization system
Entropic Corrections to Coulomb's Law
Two well-known quantum corrections to the area law have been introduced in
the literatures, namely, logarithmic and power-law corrections. Logarithmic
corrections, arises from loop quantum gravity due to thermal equilibrium
fluctuations and quantum fluctuations, while, power-law correction appears in
dealing with the entanglement of quantum fields in and out the horizon.
Inspired by Verlinde's argument on the entropic force, and assuming the quantum
corrected relation for the entropy, we propose the entropic origin for the
Coulomb's law in this note. Also we investigate the Uehling potential as a
radiative correction to Coulomb potential in 1-loop order and show that for
some value of distance the entropic corrections of the Coulomb's law is
compatible with the vacuum-polarization correction in QED. So, we derive
modified Coulomb's law as well as the entropy corrected Poisson's equation
which governing the evolution of the scalar potential . Our study further
supports the unification of gravity and electromagnetic interactions based on
the holographic principle.Comment: 17 pages, 5 figures, accepted in IJT
Corrections to Hawking-like Radiation for a Friedmann-Robertson-Walker Universe
Recently, a Hamilton-Jacobi method beyond semiclassical approximation in
black hole physics was developed by \emph{Banerjee} and
\emph{Majhi}\cite{beyond0}. In this paper, we generalize their analysis of
black holes to the case of Friedmann-Robertson-Walker (FRW) universe. It is
shown that all the higher order quantum corrections in the single particle
action are proportional to the usual semiclassical contribution. The
corrections to the Hawking-like temperature and entropy of apparent horizon for
FRW universe are also obtained. In the corrected entropy, the area law involves
logarithmic area correction together with the standard inverse power of area
term.Comment: 10 pages, no figures, comments are welcome; v2: references added and
some typoes corrected, to appear in Euro.Phys.J.C; v3:a defect corrected. We
thank Dr.Elias Vagenas for pointing out a defect of our pape
- …