Article
Physics, Particles & Fields
Polina Petriakova, Arkady A. Popov, Sergey G. Rubin
Summary: This paper discusses the origin of small parameters and aims to explain the Hierarchy problem. Flexible extra dimensions play a crucial role in the formation of physical parameters. The evolution of multidimensional metric starts from the Planck scale and ends with a static extra-dimensional metric and a 4-dimensional de Sitter space at high energies, leading to exponentially produced causally disconnected universes. Quantum fluctuations independently distort the metric within these universes, causing inflationary processes. Some universes asymptotically tend towards states characterized by small Hubble parameters. The explanation for the effective parameter reduction in the Higgs sector of the Standard Model lies in the presence of small-amplitude distributions of a scalar field in a fraction of these universes.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Yuchen Du, Shammi Tahura, Diana Vaman, Kent Yagi
Summary: The study on the effect of compact extra dimensions on gravitational wave luminosity and waveform shows significant discrepancies when compared to gravitational wave and binary pulsar observations. The findings effectively rule out the possibility of such a simple compactified higher dimensions scenario. Additional compactified extra dimensions only exacerbate the discrepancy with 4D general relativity.
Article
Astronomy & Astrophysics
Qin Tan, Wen-Di Guo, Yu-Xiao Liu
Summary: This study investigates the quasinormal modes of a thick brane system, revealing a set of discrete quasinormal modes that reflect the structural characteristics of the thick brane. These modes appear as decaying massive gravitons for a brane observer.
Article
Physics, Particles & Fields
Akash K. Mishra, Abhirup Ghosh, Sumanta Chakraborty
Summary: The presence of extra dimensions affects the spacetime geometry of rotating black holes, and the additional parameter beta modifies the quasi-normal modes. By numerically solving the gravitational field equations and analyzing data, the range of beta values is constrained, leading to implications and future directions.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Physics, Particles & Fields
Dmitry Chirkov, Alex Giacomini, Sergey A. Pavluchenko, Alexey Toporensky
Summary: The paper systematically investigates solutions with static compact extra dimensions and expanding three-dimensional subspace, providing a scheme for constructing solutions with stability analysis. It finds that solutions with negative spatial curvature of extra dimensions are always stable, while those with positive curvature are stable for a narrow range of parameters. Differences between positive and negative curvature cases, including the coexistence with maximally-symmetric solutions, are noted and discussed.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Multidisciplinary Sciences
Raja Chouket, Agnes Pellissier-Tanon, Alienor Lahlou, Ruikang Zhang, Diana Kim, Marie-Aude Plamont, Mingshu Zhang, Xi Zhang, Pingyong Xu, Nicolas Desprat, Dominique Bourgeois, Agathe Espagne, Annie Lemarchand, Thomas Le Saux, Ludovic Jullien
Summary: By illuminating reversibly photoswitchable fluorophores with different intensities, extra kinetic dimensions are introduced to overcome the limitation of label discrimination in fluorescence imaging. This strategy allows for the identification and discrimination of spectrally similar fluorescent proteins in a shorter time frame, opening promising perspectives for expanding the multiplexing capabilities of fluorescence imaging.
NATURE COMMUNICATIONS
(2022)
Article
Astronomy & Astrophysics
Maxence Corman, Abhirup Ghosh, Celia Escamilla-Rivera, Martin A. Hendry, Sylvain Marsat, Nicola Tamanini
Summary: The study explores the propagation of gravitational waves at cosmological distances, offering a new way to test modified theories of gravity at large scales. By considering a cosmological model with extra spatial dimensions, the paper derives the relation between the luminosity distance measured by GW detectors and the one inferred by EM observations. This relation is then used to constrain the number of cosmological extra dimensions and provide forecasts for future observations of massive black hole binary mergers.
Article
Astronomy & Astrophysics
S. G. Vilhena, S. B. Duarte, M. Dutra, P. J. Pompeia
Summary: We examine compact objects in modified teleparallel gravity with realistic equations of state. A modification of Teleparallel Equivalent to General Relativity is proposed, and a suitable tetrad is applied to the field equations. A specific set of relations demonstrating an equivalency between our gravitational model and the New General Relativity is discovered. This study includes numerical analysis using realistic equations of state and investigates the behavior of mass, radius, and the mass-radius relation as functions of a free parameter in our model.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Indrani Banerjee, Sumanta Chakraborty, Soumitra SenGupta
Summary: Research shows that studying the quasi-periodic oscillations around black holes can provide hints on the existence of extra spatial dimensions, with the tidal charge parameter serving as a distinctive signature of these dimensions.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
D. V. Forero, C. Giunti, C. A. Ternes, O. Tyagi
Summary: The existence of large extra dimensions can be probed in various neutrino experiments. This study shows that the gallium anomaly can be explained by neutrino oscillations induced by the large extra dimension, but the preferred parameter space is in tension with other experimental data.
Article
Astronomy & Astrophysics
Christian Ferko, Gautam Satishchandran, Savdeep Sethi
Summary: A general formalism has been developed for treating radiative degrees of freedom near I thorn in theories with an arbitrary Ricci-flat internal space. The radiative modes are encoded in a generalized news tensor which decomposes into components of gravitational, electromagnetic, and scalar. The preferred gauge simplifies the asymptotic analysis of the full nonlinear Einstein equations and extends the Bondi-Metzner-Sachs (BMS) group to include angle-dependent isometries of the internal space.
Article
Astronomy & Astrophysics
R. Jalalzadeh, S. Jalalzadeh, B. Malekolkalami
Summary: We investigate an isometrically embedded Bianchi type-V cosmology braneworld model in a D-dimensional bulk space. The model provides a fluid of geometric dark energy (GDE) and unification of fundamental forces similar to the Kaluza-Klein (KK) theory. Factors such as the Planck energy density, the fine structure constant, the muon mass, and the number of extra dimensions determine the density of the induced GDE. Our model predicts that the graviton has mass determined by the induced cosmological constant (CC). Our results suggest that if the Universe has 22 non-compact extra dimensions, they are compatible with observations of the standard model of cosmology. This model offers an alternative method for probing extra dimensions.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Astronomy & Astrophysics
M. Corman, Celia Escamilla-Rivera, M. A. Hendry
Summary: The study suggests that late-time acceleration in the universe may result from gravitational leakage into extra dimensions rather than a non-zero cosmological constant. LISA has the potential to probe and constrain the phenomenon of gravitational leakage through observations of gravitational-wave merger events, providing insights into modified gravity models.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Mathematics
R. Oset Sinha, M. A. S. Ruas, R. Wik Atique
Summary: The paper discusses extra-nice dimensions and proves the density of locally stable families under certain conditions, similar to the denseness of stable maps. It also explores the relationship between extra-nice dimensions, discriminants of germs, and simplicity of germs.
MATHEMATISCHE ANNALEN
(2022)
Article
Astronomy & Astrophysics
Pablo Bueno, Pablo A. Cano, Javier Moreno, Guido van der Velde
Summary: A plethora of new analytic black holes and globally regular horizonless spacetimes in three dimensions have been discovered, with solutions involving a single real scalar field. The new metrics are continuous generalizations of the BTZ solution, solving the Einstein gravity equations corrected by a new family of densities. Some solutions describe black holes with one or several horizons, while others have curvature singularities or are completely regular. Additionally, there are solutions describing globally regular and horizonless geometries.
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.