Article
Astronomy & Astrophysics
Yu-Qi Lei, Xian-Hui Ge
Summary: We studied the circular motion of charged particles near charged black holes and obtained the general form of the Lyapunov exponent using the Jacobian matrix. The results showed that the chaos bound can be saturated by the circular motion of charged particles on the horizon. By exploring Reissner-Nordstrom black holes with different mass-charge ratios, we found that circular motion with angular momentum can have a larger Lyapunov exponent compared to static equilibrium. We also extended our study to Reissner-Nordstrom Anti-de Sitter black holes and observed that circular motion with large angular momentum could exceed the chaos bound under specific conditions.
Article
Astronomy & Astrophysics
H. S. Vieira
Summary: In this study, we analyze the sound perturbation of Unruh's acoustic effective geometry in (2 + 1) and (3 + 1) spacetime dimensions and provide an exact analytical expression for the quasibound states of these idealized black-hole configurations. Our main objective is to discuss the impact of having an event horizon in such effective metrics. We also examine the stability of the systems and present the radial eigenfunctions associated with these quasibound state frequencies. These metrics assume the same form as a Schwarzschild black hole near the event horizon and thus can potentially offer insights into the underlying classical and quantum physics of astrophysical black holes through analog acoustic probes.
Article
Optics
Lorenzo Leone, Salvatore F. E. Oliviero, Stefano Piemontese, Sarah True, Alioscia Hamma
Summary: This study demonstrates that an information retrieval decoder can be learned using quantum machine learning in t-doped Clifford black holes when only out-of-time-order correlation functions are accessible. The fidelity of the learned decoder scales as exp(-alpha t). The crossover between learnability and nonlearnability is driven by the presence of nonstabilizerness in the black hole, and a different approach to quantum complexity is proposed.
Article
Quantum Science & Technology
Jonah Kudler-Flam, Vladimir Narovlansky, Shinsei Ryu
Summary: This work explores the distinguishability between random states and black hole microstates, calculating various generalized quantities to reveal new structures. Extending the study to random tensor networks leads to the discovery of new phenomena, enhancing the understanding of the relationship between holographic states and random tensor networks. The implications on the black hole information problem are discussed, providing new insights and solutions.
Article
Physics, Particles & Fields
Monimala Mondal, Farook Rahaman, Ksh. Newton Singh
Summary: Investigated stable and unstable equatorial circular orbits of rotating Kerr-Kiselev black holes, finding that null circular geodesics provide the fastest way to circulate around black holes with the shortest orbital period.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
Chuanhong Gao, Deyou Chen, Chengye Yu, Peng Wang
Summary: This paper investigates the chaos bound in the near-horizon region and at a certain distance from the horizon of a charged Kiselev black hole. The Lyapunov exponent is accurately calculated using a Jacobian matrix. The study finds that the bound is violated at a certain distance from the horizon, and the angular momentum of a charged particle affects both the exponent and the position of the equilibrium orbit.
Article
Astronomy & Astrophysics
Ethan Payne, Ling Sun, Kyle Kremer, Paul D. Lasky, Eric Thrane
Summary: A study has found that the presence of ultralight bosons with mass 2 x 10(-14) to mu/eV to 2 x 10(-13) can increase the rate of hierarchical black hole mergers in nuclear star clusters and result in approximately 60% more present-day nuclear star clusters supporting hierarchical growth. Furthermore, the presence of an ultralight boson can also double the rate of intermediate-mass black hole mergers to approximately 0.08 Gpc(-3) yr(-1) in the local universe.
ASTROPHYSICAL JOURNAL
(2022)
Article
Physics, Multidisciplinary
Jose Luis Jaramillo, Rodrigo Panosso Macedo, Lamis Al Sheikh
Summary: This study on the stability of quasinormal modes in asymptotically flat black hole spacetimes utilizes a pseudospectrum analysis to reveal the stability and instability under different perturbations. The analysis sheds light on the infrared effects and ultraviolet perturbations affecting the overtones of QNM, with potential implications for gravitational-wave physics and fundamental spacetime fluctuations.
Article
Astronomy & Astrophysics
Parthapratim Mahapatra, Anuradha Gupta, Marc Favata, K. G. Arun, B. S. Sathyaprakash
Summary: This study investigates the retention probability of remnants formed by hierarchical mergers in star clusters, based on the kick velocities imparted to the black hole remnants. Utilizing the gravitational-wave event database, it is found that star clusters with escape speeds of 200 km s(-1) can retain about 50% of the events in the second gravitational-wave transient catalog. The study highlights the significance of considering kick velocity inferences in future studies of hierarchical mergers.
ASTROPHYSICAL JOURNAL LETTERS
(2021)
Article
Astronomy & Astrophysics
Hiromichi Tagawa, Zoltan Haiman, Imre Bartos, Bence Kocsis, Kazuyuki Omukai
Summary: This study investigates the evidence of hierarchical mergers in recent gravitational wave observations, presenting distributions of spin parameters and chirp mass expected in these mergers. Bayesian analysis reveals certain characteristics in the data that can provide insights into the astrophysical implications of these events.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Simon Boudet, Flavio Bombacigno, Giovanni Montani, Massimiliano Rinaldi
Summary: In this study, an analytic solution describing asymptotically anti-de Sitter black holes with hyperbolic horizon is derived by considering f(R) generalizations to the Hoist action with a dynamical Immirzi field. It is shown how the behavior of the Immirzi field influences the scalar hair of the black hole and modifies the entropy law associated with it. The violation of the reverse isoperimetric inequality indicates the superentropic nature of the black hole, and the thermodynamic stability of the solution is discussed in detail.
Article
Multidisciplinary Sciences
J. A. Campos, M. A. Anacleto, F. A. Brito, E. Passos
Summary: This paper investigates the quasinormal modes for a scalar field around a noncommutative Schwarzschild black hole, and verifies the effect of noncommutativity on quasinormal frequencies using two widely used methods. It is found that the shadow radius decreases as the noncommutative parameter increases, and the shadow radius is nonzero even at the zero mass limit for finite noncommutative parameter.
SCIENTIFIC REPORTS
(2022)
Article
Astronomy & Astrophysics
Sanjar Shaymatov, Bakhtiyor Narzilloev, Ahmadjon Abdujabbarov, Cosimo Bambi
Summary: The study investigates the dynamics of neutral and charged test particles around axially symmetric magnetized black hole spacetime, showing that the combined effects of black hole electric charge and magnetic field strongly affect the innermost stable circular orbit radius. The repulsive (attractive) Coulomb force dominates over the Lorentz force from the black hole magnetic field, and increases in black hole magnetic field and electric charge lead to high center of mass energy extracted by the collision of particles. Ultimately, the presence of magnetic field in a magnetized black hole solution results in axially symmetric spacetime.
Article
Astronomy & Astrophysics
Sashwat Tanay, Leo C. Stein, Jose T. Galvez Ghersi
Summary: Researchers explored the dynamics modeling of binary black hole systems and found integrability at both 1.5PN and 2PN orders, albeit in a perturbative sense at 2PN order. This study may pave the way for a fully analytical solution to the general eccentric, spinning BBH problem.
Article
Astronomy & Astrophysics
Andre Addazi, Salvatore Capozziello, Sergei Odintsov
Summary: In this study, the emergence of black hole shadow and photon-sphere in the context of f(R) gravity is discussed, with a focus on the sensitivity of the shadow to linear instabilities of metric from f(R) solutions. It is found that the photon circular trajectories defining the black hole photon-sphere exhibit double exponential instabilities, leading to two Lyapunov exponents related to chaos in geodesic orbits. This result challenges the black hole chaos bound proposed by Maldacena, Shenker and Stanford for General Relativity, and suggests a new paradigm for handling black hole shadow and gravitational waves observations in the ringdown phase of black hole merging in Extended Theories of Gravity.
Article
Astronomy & Astrophysics
Jan E. Staff, Orsola De Marco, Daniel Macdonald, Pablo Galaviz, Jean-Claude Passy, Roberto Iaconi, Mordecai-Mark Mac Low
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2016)
Article
Astronomy & Astrophysics
Jan E. Staff, Orsola De Marco, Peter Wood, Pablo Galaviz, Jean-Claude Passy
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2016)
Article
Astronomy & Astrophysics
Pablo Galaviz, Bernd Bruegmann, Zhoujian Cao
Article
Astronomy & Astrophysics
Pablo Galaviz, Bernd Bruegmann
Article
Astronomy & Astrophysics
Zhoujian Cao, Pablo Galaviz, Li-Fang Li
Article
Biodiversity Conservation
Dan Zhang, Ee Ling Ng, Wanli Hu, Hongyuan Wang, Pablo Galaviz, Hude Yang, Wentao Sun, Chongxiao Li, Xingwang Ma, Bin Fu, Peiyi Zhao, Fulin Zhang, Shuqin Jin, Mingdong Zhou, Lianfeng Du, Chang Peng, Xuejun Zhang, Zhiyu Xu, Bin Xi, Xiaoxia Liu, Shiyou Sun, Zhenhua Cheng, Lihua Jiang, Yufeng Wang, Liang Gong, Changlin Kou, Yan Li, Youhua Ma, Dongfeng Huang, Jian Zhu, Jianwu Yao, Chaowen Lin, Song Qin, Liuqiang Zhou, Binghui He, Deli Chen, Huanchun Li, Limei Zhai, Qiuliang Lei, Shuxia Wu, Yitao Zhang, Junting Pan, Baojing Gu, Hongbin Liu
GLOBAL CHANGE BIOLOGY
(2020)
Article
Cell Biology
Jonathan Barroso-Gonzalez, Laura Garcia-Exposito, Pablo Galaviz, Michelle Lee Lynskey, Joshua A. M. Allen, SongMy Hoang, Simon C. Watkins, Hilda A. Pickett, Roderick J. O'Sullivan
Summary: Alternative lengthening of telomeres (ALT) is a telomere-elongation mechanism observed in 15% of cancer subtypes. Disruption of the MutSa DNA mismatch repair complex leads to striking telomere hyperextension in ALT cells. MutSa is specifically recruited to telomeres in ALT cells by associating with the PCNA subunit of the replisome, counteracting the role of BLM helicase in stabilizing hyper-extended telomeres and maintaining the survival of MutSa-deficient ALT cancer cells.
Article
Biochemical Research Methods
Robert Lu, Joshua A. M. Allen, Pablo Galaviz, Hilda A. Pickett
Summary: This study presents a DNA-fiber protocol combining YOYO-1 staining, telomere fluorescence in situ hybridization (FISH), and EdU labeling to measure telomere extension events in ALT cancer cells.
Article
Astronomy & Astrophysics
Pablo Galaviz, Orsola De Marco, Jean-Claude Passy, Jan E. Staff, Roberto Iaconi
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2017)
