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Related papers: Testing loop quantum gravity by quasi-periodic osc…

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There is rich literature on regular black holes from loop quantum gravity (LQG), where quantum geometry effects resolve the singularity, leading to a quantum extension of the classical space-time. As we will see, the mechanism that resolves…

General Relativity and Quantum Cosmology · Physics 2023-01-05 Abhay Ashtekar , Javier Olmedo , Parampreet Singh

We investigate a recently derived Schwarzschild-like black hole immersed in a Dehnen-type $(\alpha,\beta,\gamma)=(1,4,5/2)$ dark matter (DM) halo. We obtain constraints on the two model parameters, i.e., the halo core radius $r_s$ and the…

General Relativity and Quantum Cosmology · Physics 2025-10-29 Tursunali Xamidov , Sanjar Shaymatov , Qiang Wu , Tao Zhu

We investigate the black hole information paradox in the setting of pseudo-complex gravity, a covariant geometric extension of general relativity that introduces a minimal length scale by deforming the spacetime manifold. In this framework,…

General Relativity and Quantum Cosmology · Physics 2025-06-30 Fridolin Weberand Peter O. Hess , Cesar A. Zen Vasconcellos

This study investigates the properties of the thin accretion disk around a black hole in quantum fluctuation modified gravity (QFMGBH) using the Novikov-Thorne model. We restrict the parameter \( \alpha \) characterizing the quantum…

General Relativity and Quantum Cosmology · Physics 2025-09-09 Jiajun Yin , Tong-Yu He , Ming Liu , Hui-Min Fan , Bohai Chen , Zhan-Wen Han , Rong-Jia Yang

The presence of spacetime singularities in physically relevant solutions of the Einstein Equations is normally interpreted as a symptom of the breakdown of classical general relativity at very high densities/curvatures. However, despite…

General Relativity and Quantum Cosmology · Physics 2022-11-08 Shafqat Riaz , Swarnim Shashank , Rittick Roy , Askar B. Abdikamalov , Dimitry Ayzenberg , Cosimo Bambi , Zuobin Zhang , Menglei Zhou

We propose a unified model to explain Quasi-Periodic-Oscillation (QPO), particularly of high frequency, observed from black hole and neutron star systems globally. We consider accreting systems to be damped harmonic oscillators exhibiting…

Astrophysics · Physics 2011-02-11 Banibrata Mukhopadhyay

We compute asymptotic Quasi-Normal Mode (QNM) frequencies -- i.e. frequencies with a very large Imaginary part -- of a Loop Quantum Gravity inspired Black Hole. The deformations from the Schwarzschild Black Hole are encoded via two…

General Relativity and Quantum Cosmology · Physics 2025-10-30 Clara Montagnon

We study motion of charged particles in the field of a rotating black hole immersed into an external asymptotically uniform magnetic field, focusing on the epicyclic quasi-circular orbits near the equatorial plane. Separating the circular…

General Relativity and Quantum Cosmology · Physics 2016-05-04 Arman Tursunov , Zdeněk Stuchlík , Martin Kološ

The shocked wave created on the accretion disk after different physical phenomena (accretion flows with pressure gradients, star-disk interaction etc.) may be responsible observed Quasi Periodic Oscillations (QPOs) in $X-$ray binaries. We…

Astrophysics · Physics 2008-11-26 Orhan Donmez

In this paper, we investigate the impact of loop quantum gravity (LQG) on extreme mass-ratio inspirals (EMRIs), and the results indicate that LQG effects cause the orbital decay to occur faster compared to the Schwarzschild case.…

General Relativity and Quantum Cosmology · Physics 2024-09-20 Guoyang Fu , Yunqi Liu , Bin Wang , Jian-Pin Wu , Chao Zhang

{\it Hunting} compact astrophysical objects such as black holes and wormholes, as well as testing gravity theories, are important issues in relativistic astrophysics. In this sense, theoretical and observational studies of quasiperiodic…

General Relativity and Quantum Cosmology · Physics 2024-03-14 Farukh Abdulkhamidov , Petya Nedkova , Javlon Rayibaev , Jutta Kunz , Bobomurat Ahmedov

This paper investigates the high frequency quasi-periodic oscillations (HFQPOs) phenomenon around the black bounce-type (BBT) spacetime using the resonance models. We calculated the location of the innermost stable circular orbit (ISCO) for…

General Relativity and Quantum Cosmology · Physics 2024-12-18 Jianbo Lu , Shining Yang , Yuying Zhang , Liu Yang , Mou Xu

We reexmine some proposals of black hole entropy in loop quantum gravity (LQG) and consider a new possible choice of the Immirzi parameter which has not been pointed out so far. We also discuss that a new idea is inevitable if we regard the…

High Energy Physics - Theory · Physics 2009-11-11 Takashi Tamaki , Hidefumi Nomura

In this paper we investigate the innermost stable circular orbit (ISCO) for a classical spinning test particle in the background of Kerr-Newman black hole. It is shown that the orbit of the spinning particle is related to the spin of the…

General Relativity and Quantum Cosmology · Physics 2018-05-02 Yu-Peng Zhang , Shao-Wen Wei , Wen-Di Guo , Tao-Tao Sui , Yu-Xiao Liu

After black holes collide, the remnant settles to a stationary state by emitting gravitational waves. Once non-linearities subside, these ringdown waves are dominated by exponentially-damped sinusoids, or quasinormal modes. We develop a…

General Relativity and Quantum Cosmology · Physics 2024-11-05 Adrian Ka-Wai Chung , Nicolas Yunes

The innermost stable circular orbit (ISCO) offers a fundamental test of spacetime structure. However, its behavior in higher-dimensional black holes influenced by anisotropic energy-momentum tensors remains insufficiently explored. In this…

General Relativity and Quantum Cosmology · Physics 2025-11-18 Hocheol Lee , Bogeun Gwak

Astrophysical black holes are often embedded into electromagnetic fields, that can usually be treated as test fields not influencing the spacetime geometry. Here we analyse the innermost stable circular orbit (ISCO) of charged particles…

General Relativity and Quantum Cosmology · Physics 2020-03-11 Jan P. Hackstein , Eva Hackmann

Future very-large-area X-ray instruments (for which the effective area is larger than $>3$m$^2$) will be able to measure the frequencies of quasi-periodic oscillations~(QPOs) observed in the X-ray flux from accreting compact objects with…

High Energy Astrophysical Phenomena · Physics 2017-07-05 Andrea Maselli , Paolo Pani , Roberto Cotesta , Leonardo Gualtieri , Valeria Ferrari , Luigi Stella

In order to search for the evidence of quasi-periodic oscillation (QPO) in blazar, multicolor optical observations of the BL Lacertae object S5 0716+714 were performed from 2005 to 2012. For $I$ band on March 19 2010 with low variability…

High Energy Astrophysical Phenomena · Physics 2017-12-27 Shanwei Hong , Dingrong Xiong , Jinming Bai

We present, in closed analytic form, a general stationary, slowly rotating black hole, which is solution to a large class of alternative theories of gravity in four dimensions. In these theories, the Einstein-Hilbert action is supplemented…

General Relativity and Quantum Cosmology · Physics 2011-10-27 Paolo Pani , Caio F. B. Macedo , Luis C. B. Crispino , Vitor Cardoso