arXiv subjects

Yu-Hang Feng

Publications and source records attributed to Yu-Hang Feng.

3 recordsLinked to original sources

arXiv2024

Thermodynamics of AdS-Schwarzschild-like black hole in loop quantum gravity

We obtained the metric of the Schwarzschild-like black hole with loop quantum gravity (LQG) corrections in anti-de Sitter (AdS) space-time, under the assumption that the cosmological constant is decoupled in LQG. We investigated its thermodynamics, including the equation of state, criticality, heat capacity, and Gibbs free energy. The $P-v$ graph was plotted, and the critical behavior was calculated. It was found that, due to the LQG effect, the quantum-corrected Schwarzschild-AdS black hole exhibits a critical point and a critical ratio of $7/18$, which differs from the Reissner-Nordstr$\ddot{\mathrm{o}}$m-AdS black hole's ratio of $3/8$ (the same as that of the Van der Waals system) slightly. However, there are still some similarities compared to the Van der Waals system, such as the same critical exponents and a similar $P-v$ graph. Moreover, it is concluded that the energy-momentum tensor related to the black hole's mass could violate the conventional first law of thermodynamics. This modified first law may violate the conservation of Gibbs free energy during the small black hole-large black hole phase transitions, potentially indicating the occurrence of the zeroth-order phase transition. The Joule-Thomson expansion was also studied. Interestingly, compared to the Schwarzschild-AdS black hole, the LQG effect leads to inversion points. The inversion curve divides the $\left(P,T\right)$ coordinate system into two regions: a heating region and a cooling region, as shown in detail by the inversion curves and isenthalpic curves. The results indicated that there is a minimum inversion mass, below which any black hole will not possess an inversion point.

gr-qc↗

arXiv2024

Decoding quantum gravity information with black hole accretion disk

The combination of Loop Quantum Gravity theory with the classical gravitational collapse model has effectively addressed the singularity problem of black holes and predicted the emergence of white holes in the late stages of collapse. The quantum extension of Kruskal spacetime suggests that the appearance of white holes may carry information from companion black holes in the universe earlier than ours. Photons emitted from the accretion disk of companion black holes will enter the companion black hole, traverse through quantum regions from the white hole to our universe, and produce imaging of accretion disk carrying quantum gravity information. In our work, we have obtained the accretion disk images of black hole from a universe earlier than ours, transported by a white hole within our universe, along with the positions and widths of these images exactly. Remarkably, behaviours of white hole and black hole imaging are similar in photon sphere and contrary to some cases of outside. This will provide valuable references for astronomical observations to validate quantum gravity theory.

gr-qc↗

arXiv2022

Double shadow of a 4D Einstein-Gauss-Bonnet black hole and their connection between with quasinormal modes

In this paper, we study the shadow of a 4D Einstein-Gauss-Bonnet black hole as photons couple to the Weyl tensor and find that the propagation of light depends on its polarization which leads to the existence of a double shadow. Then, we discuss the effect of the coupling parameter $λ$, the polarization of light and the Gauss-Bonnet coupling constant $α$ on shadow. Further we explore the influence of the Gauss-Bonnet coupling constant $α$ on the quasinormal modes (QNMs) of massless scalar field and investigate the connection between the real part of QNMs in the eikonal limit and the shadow radius of black holes. We find that in the eikonal limit the real part of QNMs is inversely proportional to the shadow radius under the case of the photons uncoupled to the Weyl tensor.

gr-qc↗