arXiv subjects

Arpita Jana

Publications and source records attributed to Arpita Jana.

6 recordsLinked to original sources

arXiv2026

Spin-curvature effects in slowly rotating black hole spacetime

We investigate the spin-curvature interaction for a massive spin-1/2 quantum particle in a slowly rotating black hole spacetime. In contrast to the flat Minkowski space, the curved spacetime introduces non-trivial spin connections into the Dirac equation due to the direct curvature-spin interaction. The force arising from this non-trivial spin-curvature coupling makes the particle deviate from its geodesics. We first calculate the tetrads in the co-moving frame of the particle in the slowly rotating black hole background. We then compute the components of the relativistic quantum force, arising from the spin-curvature interaction, using these co-moving tetrads up to linear order in the rotation parameter ($a$) of the black hole. The procedure of computing the force is based on the WKB approximation and the Gordon decomposition method for the Dirac probability four current. Our results show that the rotation parameter modifies the magnitude of the force by introducing a term that decays more rapidly with radial distance than the force magnitude in a static spherically symmetric Schwarzschild black hole spacetime.

hep-th↗

arXiv2026

Quantum corrections to the black hole entropy using the brick wall model

It was suggested by 't Hooft that to avoid the divergence of the free energy or entropy of the probe fields, one has to introduce an infrared (IR) cutoff. This introduction of the IR cutoff, namely, the brick wall model, has been studied for the Schwarzschild black hole and has been shown by 't Hooft that to have the entropy of the order of Bekenstein-Hawking entropy, the cutoff must be of the order of Planck length. In this study, we investigated the brick wall model in the context of a Reissner-Nordstróm, quantum corrected Schwarzschild and quantum corrected Reissner-Nordström black holes. In particular, we have shown that the brick wall model can give logarithmic correction to the black hole entropy in the subleading order. The important aspect of our analysis is that we have not considered the near horizon approximation of the lapse function and get more accurate correction to the entropy. This corrected entropy has an important feature that it is larger than the usual Bekenstein-Hawking entropy which aligns with the result of Barrow entropy.

hep-th↗

arXiv2026

Quasi-normal modes of quantum gravity black hole with perfectly fluid dark matter

In this work, we have studied the motion of a massless scalar photon in the renormalization group (RG) improved Schwarzschild black hole spacetime in the presence of perfectly fluid dark matter (PFDM). Considering the critical orbit conditions and the null geodesics condition in static spherically sym- In metric geometry, we have shown the variation of the radius of the photon sphere $r_{ph}$ with the PFDM parameter $ζ$. Due to perturbations in black hole spacetime, gravitational waves are emitted in the form of quasi-normal radiations, which correspond to quasi-normal modes (QNMs). In this work, we have studied two types of perturbations in RG improved Schwarzschild spacetime: scalar field perturbations and electromagnetic (EM) field perturbations. For both cases, we have studied the effect of the PFDM parameter on the quasi-normal mode frequencies and the shadow of the black hole, which is related to the photon radius.

gr-qc↗

arXiv2025

Area spectrum and black hole thermodynamics

The role of horizon area quantization on black hole thermodynamics is investigated in this article. The coefficient appearing in the quantization of area is fixed by an appeal to the saturated form of the Landauer's principle. Then by considering transition between discrete states of the event horizon area which in turn is equivalent to transitions between discrete mass states of the black hole, the change in the mass can be obtained. The change in mass is then equated to the product of the Hawking temperature and change in entropy of the black hole between two consecutive discrete states applying the first law of black hole thermodynamics. This gives the corrected Hawking temperature. In particular, we apply this technique to the Schwarzschild black hole, the quantum corrected Schwarzschild black hole, the Reissner-Nordström black hole which is a charged black hole, and the rotating Kerr black hole geometry, and obtain the corrected Hawking temperature in each of these cases. We then take a step forward by inserting this corrected Hawking temperature in the first law of black hole thermodynamics once again to calculate the entropy of the black hole in terms of the horizon area of the black hole. This leads to logarithmic and inverse corrections to the entropy of the black hole.

gr-qc↗

arXiv2025

Inverse logarithmic correction in the HBAR entropy of an atom falling into a renormalization group improved charged black hole

In this work, we have considered a spherically symmetric non-rotating charged black hole geometry where both the Newton's gravitational constant and the charge of the black hole flows with the energy scale. We have used the Kretschmann scale identification to write down the finite cutoff for the momentum scale in terms of the proper distance. Introducing the flow of running couplings, the event horizon radius of the black hole using quantum improved Reissner-Nordstrom metric was found in \href{https://doi.org/10.1103/PhysRevD.104.066016}{Phys. Rev. D 104 (2021) 066016}. We have, in this work, explored the thought experiment of a two-level atom freely falling into the event horizon of a quantum improved charged black hole and have computed the transition probability of the atom for going from its ground state to the excited state via emission of a virtual photon. We find that the probability deviates slightly from the pure Planckian spectrum. We have showed that this deviation is due to the presence of incomplete lower gamma function in the distribution function. We have then computed the horizon brightened acceleration radiation entropy and found that it is identical to the Bekenstein-Hawking entropy followed by the renormalization group correction terms including an inverse logarithmic and a square root of the area term due to emitting photons.

gr-qc↗

arXiv2024

Atom falling into a quantum corrected charged black hole and HBAR entropy

In an earlier analysis \href{https://link.aps.org/doi/10.1103/PhysRevD.105.085007}{Phys. Rev. D 105 (2022) 085007}, we have explored the event of acceleration radiation for an atom freely falling into the event horizon of a quantum-corrected Schwarzschild black hole. We want to explore the acceleration-radiation when the atom is freely falling into the event horizon of a charged quantum-corrected black hole. We consider the quantum effects of the electromagnetic field along with the gravitational field in an asymptotic safety regime. Introducing the quantum improved Reisner-Nordström metric, we have calculated the excitation probability of a two-level atom freely falling into the event horizon of quantum improved charged black hole. Recently, in the case of the braneworld black hole (where the tidal charge has the same dimension as the square of the charge of a Reissner-Nordström black hole in natural units), we have observed from the form of the transition probability that the temperature will have no contribution in the first order of the tidal charge. We observe that for a quantum corrected Reissner-Nordström black hole, there is a second-order contribution in the charge parameter in the temperature that can be read off from the transition probability. Next, we calculate the HBAR entropy in this thought experiment and show that this entropy has a leading order Bekenstein-Hawking entropy term along with some higher order correction terms involving logarithmic as well as fractional terms of the black hole area due to infalling photons. We have finally investigated the validity of Wien's displacement law and compared the critical value of the field wavelength with the general Schwarzschild black hole and its corresponding quantum-corrected case.

gr-qc↗