Article
Physics, Particles & Fields
Gustav Mogull, Jan Plefka, Jan Steinhoff
Summary: This study establishes a precise connection between scalar-graviton S-matrix elements and expectation values of operators in a worldline quantum field theory, both of which are used to describe the classical scattering of black holes. By introducing a new set of Feynman rules, the study obtains results related to three-body gravitational radiation and two-body deflection in black hole scattering events. Furthermore, the study reveals that the eikonal phase of a 2 -> 2 scalar S-matrix corresponds to the free energy of the worldline quantum field theory.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Astronomy & Astrophysics
Cristian Erices, Pantelis Filis, Eleftherios Papantonopoulos
Summary: The study demonstrates the avoidance of the no-hair theorem in scalar-tensor theories with bimetric structure by introducing an electric charge, leading to black hole solutions with rich thermodynamic behavior. The interplay of stability and phase transitions between different black hole configurations resembles a solid-liquid-gas system, with an electric potential acting as pressure and a triple point where three phases coexist equally probable.
Article
Physics, Particles & Fields
Alex Davey, Oscar J. C. Dias, Paul Rodgers
Summary: The article investigates the phase diagram of solutions of the charged black hole bomb system, particularly focusing on static hairy black holes in the Einstein-Maxwell-Scalar theory. These hairy black holes have higher entropy and may serve as the endpoint of instabilities in the black hole bomb system, relating to boson stars in the theory.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Jie Jiang, Aofei Sang, Ming Zhang
Summary: This paper investigates the effects of quantum corrections of the Einstein-Maxwell theory on the first law of black hole thermodynamics. The results suggest that the first law might still hold in the effective region, even with the inclusion of higher-curvature terms and nonminimally coupled electromagnetic fields.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Guangzhou Guo, Peng Wang, Houwen Wu, Haitang Yang
Summary: This study investigates the time evolutions of charged scalar perturbations on the background of a charged hairy black hole. By analyzing the quasinormal modes extracted from the waveform of scalar perturbations, it is discovered that some quasinormal modes can be superradiantly amplified when trapped in a potential well between two potential peaks. These superradiant modes render the charged hairy black hole unstable against charged scalar perturbations.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
Kun Meng, Xi-Long Fan, Song Li, Wen-Biao Han, Hongsheng Zhang
Summary: The deviation parameters of Johannsen black holes are constrained for the first time using observations of M87* and SgrA*, revealing their effects on the black hole shadow and accretion disk. Observations with higher sensitivities in the future can test the effects of these parameters.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
Oscar J. C. Dias, Takaaki Ishii, Keiju Murata, Jorge E. Santos, Benson Way
Summary: We construct a cohomogeneity-1 helical black string in six-dimensional Einstein gravity originating from the superradiant instability of the Myers-Perry black string. The helical black string possesses helical isometries generated by linear combinations of time translation, shifts along the string, and rotation, which are individually broken by the superradiant instability. Despite the absence of momentum in the string direction, the helical black string exhibits nonzero horizon velocity.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
Marco Astorino, Roberto Emparan, Adriano Vigano
Summary: This paper argues that expanding bubbles of nothing are a common feature in systems of black holes with multiple or non-spherical horizons. The authors provide explicit constructions in four and five dimensions to demonstrate this idea, showing that the geometries of expanding bubbles arise as a limit of static black hole binaries and black rings. They also discuss the possibility of similar constructions in higher dimensions, although numerical methods are often required. The paper concludes by suggesting that the Nariai solution can be understood as containing an expanding circular bubble of nothing.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Chaoxi Fang, Jie Jiang, Ming Zhang
Summary: In the generalized off-shell free energy landscape, black holes are considered as thermodynamic topological defects. The local topological properties are reflected by the winding numbers at the defects, while the global topological nature can be classified by the topological number which is the sum of all local winding numbers. The winding numbers can be calculated via the residues of isolated one-order pole points of characterized functions constructed from the off-shell free energy. The topologies of black holes can be divided into three classes with the topological numbers being -1, 0, and 1, respectively, consistent with the results obtained in [Phys. Rev. Lett. 129, 191101 (2022)] using the topological current method. Standard defect points, generation and annihilation points, and critical points can be distinguished by coefficients of the Laurent series of the off-shell characterized function at those singular points.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
Lam Hui, Austin Joyce, Riccardo Penco, Luca Santoni, Adam R. Solomon
Summary: We study the near-zone symmetries of a massless scalar field on four-dimensional black hole backgrounds and provide a geometric understanding that unifies various recently discovered symmetries as part of an SO(4, 2) group. A subset of these symmetries corresponds to the static sector and leads to the ladder symmetries responsible for the vanishing of Love numbers. We compare different near-zone approximations in the literature for the Kerr case and focus on the implementation that retains the symmetries of the static limit. We also describe the relation to spin-1 and 2 perturbations.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Guangzhou Guo, Peng Wang, Houwen Wu, Haitang Yang
Summary: This study investigates the waveforms of time signals produced by scalar perturbations in static hairy black holes. The waveforms are influenced by a double-peak effective potential. When the distance between the peaks is large, a series of decaying echo pulses are generated. However, when the peaks are close, fewer echo signals and a slowly decaying sinusoid tail are observed.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Guangzhou Guo, Peng Wang, Houwen Wu, Haitang Yang
Summary: In this paper, scalarized rotating black holes are constructed within the framework of Einstein-Maxwell-scalar models. The presence of scalarized KN black holes is suppressed by the black hole spin, with a maximum spin threshold. Furthermore, the paper observes the existence of unstable and stable light rings on the equatorial plane in specific parameter regimes for scalarized KN black holes.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Article
Physics, Particles & Fields
Ricardo Monteiro, Donal O'Connell, David Peinador Veiga, Matteo Sergola
Summary: The study demonstrates that classical objects computed by massive three-point amplitudes in gauge theory and gravity are Newman-Penrose scalars in a split-signature spacetime. These three-point amplitudes can define real kinematics and the quantum state set up by the particle is a coherent state fully determined by the three-point amplitude.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
David Licht, Raimon Luna, Ryotaku Suzuki
Summary: We investigate the phase space of non-uniform black branes on oblique lattices with numerous dimensions. We discover the phase diagrams for various periodicities and angles, and identify the thermodynamically favored phases for each lattice configuration. In a specific range of angles, we observe the metastability of certain phases.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Physics, Particles & Fields
Ryotaku Suzuki, Shinya Tomizawa
Summary: This study constructs static solutions of non-extremal and squashed black holes using the large D effective theory approach, describing spherical black holes in a Kaluza-Klein spacetime with a compactified dimension. The asymptotic background and near-horizon geometry with a compactified dimension are analytically solved by the 1/D expansion. Additionally, the large D limit is shown to be applicable in solving non-trivial backgrounds with a compactified direction, leading to a first-order flow equation, and the extremal limit reproducibly produces known results.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Astronomy & Astrophysics
T. Padmanabhan, Sumanta Chakraborty
Summary: In the paradigm of effective field theory, this study explores integrating out high energy degrees of freedom to obtain effective actions for low energy degrees of freedom, as well as deriving effective actions by integrating out a vector field in an action. The results predict the presence of a non-zero cosmological constant and discuss the implications of this approach.
Article
Physics, Particles & Fields
Sumanta Chakraborty, Debodirna Ghosh, Sk Jahanur Hoque, Aniket Khairnar, Amitabh Virmani
Summary: The paper proposes a definition of asymptotic flatness at timelike infinity in four spacetime dimensions and studies the asymptotic equations of motion and the action of supertranslations in detail. It demonstrates that the Lee-Wald symplectic form does not receive contributions from future timelike infinity with the specified boundary conditions, allowing for the computation of future charges on any two-dimensional surface surrounding the sources at timelike infinity. Expressions for supertranslation and Lorentz charges are presented.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Astronomy & Astrophysics
Sumanta Chakraborty, Supratik Pal, Soumitra SenGupta
Summary: This paper presents a fundamental origin for the primordial magnetic field generated in the early universe, and analyzes its power spectrum and characteristics. The study finds that the model can produce a magnetic field with helical nature and significant scale-dependence, with a large parameter space for generating magnetic field of sufficient strength.
Article
Astronomy & Astrophysics
Sumanta Chakraborty, Subir Ghosh
Summary: This study investigates gravitational perturbations around maximally symmetric backgrounds in a theory of gravity involving quadratic curvature corrections, revealing an additional scalar degree of freedom and discussing possible ground state selections and time crystal forms.
PHYSICS OF THE DARK UNIVERSE
(2022)
Article
Astronomy & Astrophysics
Justin C. Feng, Sumanta Chakraborty
Summary: In this study, the Weiss variation of the Einstein-Hilbert action with an appropriate boundary term is investigated for general boundary surfaces. By introducing an auxiliary reference connection, we find that the Weiss variation yields the expected Einstein equations, along with additional boundary contributions. Regardless of the nature of the boundary surface, whether spacelike, timelike, or null, we obtain the dynamical variable and conjugate momentum. Additionally, we derive the generally non-vanishing covariant generalization of the Einstein energy-momentum pseudotensor and discuss its implications.
GENERAL RELATIVITY AND GRAVITATION
(2022)
Article
Physics, Particles & Fields
Chiranjeeb Singha, Sumanta Chakraborty, Naresh Dadhich
Summary: The strong cosmic censorship conjecture has been validated for charged BTZ black holes and in certain gravitational theories. The study demonstrates that the key parameter associated with violation of the conjecture is always below the critical value in these cases, in contrast to higher dimensional black holes.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
Article
Astronomy & Astrophysics
Sajal Mukherjee, Sumanta Chakraborty
Summary: In this article, we discuss the late inspiral and transition regime to the plunge phase of a less massive compact object into a more massive braneworld black hole, considering an extreme-mass-ratio inspiral system. We derive approximate expressions for fluxes due to slowly evolving constants of motion and introduce dissipative effects to model the inspiral. We qualitatively understand the impact of the additional tidal charge in the braneworld scenario on the timescale of the late inspiral to the plunge.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Physics, Particles & Fields
Sumanta Chakraborty, Naresh Dadhich
Summary: The Buchdahl sphere, a stable isotropic stellar structure without exotic matter, is crucial in our comprehension of the compactness of astrophysical objects. We have identified universal properties associated with the Buchdahl sphere that remain unchanged even with the inclusion of electric charge or in pure Lovelock gravity theories. Utilizing these universalities, we have introduced the Buchdahl limit for slowly-rotating stellar configurations for the first time. Furthermore, we have discussed the universality of the Buchdahl sphere in relation to gravitational and non-gravitational field energies, as well as the photon sphere.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Justin C. Feng, Sumanta Chakraborty, Vitor Cardoso
Summary: We propose a shielding mechanism for a charged black hole in the presence of charged matter fields based on the Einstein-Maxwell field equations. By considering a charged generalization of the Einstein cluster, we demonstrate the existence of this shielding mechanism in different parameterizations. Additionally, we provide the most general electrovacuum solution in a charge-free spacetime region but with a static and spherically symmetric charge distribution elsewhere, as well as a convenient parameterization for the global solution of the Einstein-Maxwell's field equations in the presence of a charged black hole and charged fluid environment. Furthermore, we discuss the properties of the photon sphere, shadow radius, and eikonal quasinormal modes in the Einstein-Maxwell cluster.
Article
Astronomy & Astrophysics
Edgardo Franzin, Stefano Liberati, Jacopo Mazza, Ramit Dey, Sumanta Chakraborty
Summary: This study investigates scalar test-field perturbations on a Kerr-black-bounce background, exploring rotating regular black holes and/or rotating traversable wormholes. The research confirms the stability of regular black holes and identifies a set of growing modes that render traversable wormholes unstable.
Article
Astronomy & Astrophysics
Indranil Chakraborty, Soumya Bhattacharya, Sumanta Chakraborty
Summary: This study investigates the gravitational wave memory effect in a certain class of braneworld wormholes. Through the analysis of geodesic evolution and memory effects at null infinity in a braneworld wormhole, it reveals the imprint of extra dimensions and wormhole nature in the memory effect. This work provides an alternative approach to search for compact objects other than black holes, as future gravitational wave detectors will be able to probe the memory effect.
Article
Biotechnology & Applied Microbiology
Sumanta Chakraborty
Summary: This study evaluated the cyto-genotoxic potential of fruit extract from Cestrum diurnum on Onion root apical meristem cells, and found that it caused mitotic anomalies and micronuclei induction. Phytochemical analysis confirmed the presence of various secondary metabolites in the fruit extract. However, caution is necessary when using herbal preparations.
APPLIED BIOLOGICAL RESEARCH
(2022)
Article
Astronomy & Astrophysics
Shauvik Biswas, Mostafizur Rahman, Sumanta Chakraborty
Summary: This study investigates the stability of wormhole geometries in higher dimensional spacetimes and the phenomenon of gravitational wave echoes. The results show that exotic matter fields are not necessary to construct wormholes in higher dimensional spacetimes. It is also found that the axial gravitational perturbations in wormhole spacetimes exhibit a distinct effective potential compared to scenarios involving black holes. Furthermore, the analysis using both analytical and numerical techniques reveals the existence of echoes in the time domain signal of all perturbations, with the delay time being intimately related to the parameters from higher dimensions.
Article
Astronomy & Astrophysics
Indrani Banerjee, Sumanta Chakraborty, Soumitra SenGupta
Summary: Our study shows that the observed angular diameter of the shadow of the ultracompact object Sgr A* supports the existence of an extra spatial dimension. This result remains consistent regardless of whether Sgr A* is a wormhole or a black hole mimicker, as both have an extra dimensional origin. Furthermore, this result holds true for mass and distance measurements obtained from both Keck and Gravity collaborations, and whether the observed image or the observed shadow diameter is used. Specifically, the central value of the observed shadow or image diameter predicts the presence of nonzero hairs inherited from the extra dimensions.
Article
Astronomy & Astrophysics
Sumanta Chakraborty, Elisa Maggio, Anupam Mazumdar, Paolo Pani
Summary: Motivated by capturing putative quantum effects at the horizon scale, this study models the black hole horizon as a fluctuating membrane and investigates the quantum nature's influence on the boundary conditions and reflectivity. Echoes in the postmerger signal are found to exist as a result. Additionally, the horizon boundary condition for a braneworld black hole originating from quantum corrections on the brane is derived, leading to a modified gravitational-wave ringdown.