2.4k citations · 12k across the 222 of their papers we have counts for
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Swampland diagnostics and observational tests of the inflationary universe in the Palatini formalism
Saeed Noori Gashti, Mohammad Reza Alipour, Mohammad Ali S. Afshar +1
We consider quintessential inflation in a quadratic Palatini model with a generalized Peebles-Vilenkin potential, where the same scalar field describes both the inflationary platea…
Noether and Mei symmetries in static spherically symmetric quadratic gravity: variational consistency, constraints, and conserved curvature flux
G. G. N. Nashed, A. Eid, Kazuharu Bamba
The symmetry content of static spherical gravity is reconsidered for the pure quadratic model. We first derive the radial action without prematurely eliminating the equation…
Evolving wormhole cosmology: modified Friedmann dynamics and observational constraints
Aritra Sanyal, Kazuharu Bamba, Prabir Rudra
We construct an evolving wormhole cosmological model from a Morris--Thorne metric with a separable, time-dependent shape function in a spatially flat Friedmann--Lemaitre--Robertson…
Higher-order generalized uncertainty principle corrections to Casimir-supported traversable wormholes
Jureeporn Yuennan, Allah Ditta, Thammarong Eadkhong +2
We investigate traversable wormholes supported by Casimir vacuum energy with second-order generalized uncertainty principle (GUP) corrections. For two representative GUP models, we…
Reconstruction of a dark energy model for the Dirac-Born-Infeld scalar field with the Hubble and DESI data via Gaussian process
Sayantan Ghosh, Gaurav N. Gadbail, P. K. Sahoo +1
In this study, we reconstruct the dark energy (DE) as a Dirac-Born-Infeld (DBI) scalar field from the Hubble dataset (32 CC + 26 BAO) and the DESI dataset using the Gaussian proces…
Gravitational wave echoes as probes of the maximum mass of strange stars in quadratic curvature-matter coupled gravity
Debadri Bhattacharjee, Pradip Kumar Chattopadhyay, Kazuharu Bamba
Gravitational wave astronomy provides a powerful avenue for probing exotic compact stars. Recent analyses of GW170817 have reported possible post-merger gravitational wave echoes w…
Tidal deformation of an accreting compact object
Avijit Chowdhury, Chiranjeeb Singha, Kazuharu Bamba +1
Tidal deformation of a compact object serves as a sensitive probe of the strong-gravity regime and nature of the compact object. It captures how a compact object responds to the ex…
Regular black holes with Minkowskian cores: causal structure and observational degeneracy
Francisco Tello-Ortiz, Y. Gómez-Leyton, Alejandro Rueda +2
We construct a new family of asymptotically flat static and rotating regular black holes characterized by a Minkowskian core and a finite two-horizon structure. The solutions are o…
Geometric effects of torsion on black hole ringdown and shadows in Poincaré gauge gravity
Terkaa Victor Targema, Kazuharu Bamba, Riasat Ali +1
Spacetime torsion provides a natural extension of general relativity and may lead to black hole solutions that differ significantly from their Einsteinian counterparts. We investig…
Rotating traversable wormholes and particle dynamics in gravity
G. G. L. Nashed, Waleed El Hanafy, Amare Abebe +2
Traversable wormholes are among the most interesting solutions of gravitational theories, but within General Relativity they generally require exotic matter violating the null ener…
Thermodynamics and optical aspects of ModMax black holes in higher order curvature gravity with quintessence dark energy
Ahmad Al-Badawi, Usman Zafar, Abdul Jawad +1
In this work, we derive an exact black hole solution in higher-order curvature gravity by coupling an electromagnetic sector formulated within the ModMax framework to a quintessenc…
On the Maldacena-Shenker-Stanford chaos bound in black hole spacetimes: Saturation, apparent violations, and their geometric origin
Terkaa Victor Targema, Kazuharu Bamba, Usman Zafar
Reported violations of the Maldacena-Shenker-Stanford (MSS) chaos bound in black hole spacetimes raise the question of whether they reflect a genuine breakdown, a feature of partic…
Generalized First Law and Smarr-type Relation: Beyond Additivity and Extensivity
Usman Zafar, Krishnakanta Bhattacharya, Kazuharu Bamba
In this work, we develop a general framework for deriving the first law of black hole thermodynamics and the associated Smarr-type relation for 4-dimensional static spherically sym…
Testing CDM with ANN-Reconstructed Expansion History from Cosmic Chronometers
Yuki Hashimoto, Kazuharu Bamba, Sanjay Mandal
In modern cosmology, the rapid growth of high-precision observational data, along with significant theoretical advances, has intensified the challenge of identifying a robust, mode…
A sound-horizon-free measurement of the Hubble constant from DESI DR2 baryon acoustic oscillations using artificial neural networks
Gaurav N. Gadbail, Kazuharu Bamba
We present a model-independent, sound-horizon-free measurement of the Hubble constant using baryon acoustic oscillation tracers from the Dark Energy Spectroscopic Instrument…
Thermodynamic Topology and Photon Spheres Analysis of Black Holes in Brane-World: Insights from Barrow Entropy
Usman Zafar, Abdul Jawad, Kazuharu Bamba +4
We explore the thermodynamics and geothermodynamics of black holes with Barrow entropy in a brane-world scenario, where the horizon geometry of the black hole is regarded as a frac…
Energy conditions of bouncing solutions in quadratic curvature gravity coupled with a scalar field
Yuki Hashimoto, Kazuharu Bamba, Sanjay Mandal
We examine the validity of classical energy conditions in nonsingular bouncing cosmological solutions arising in quadratic curvature gravity minimally coupled to a scalar field. Fo…
Gravastars on the brane with a timelike extra dimension
Shounak Ghosh, Rikpratik Sengupta, Kazuharu Bamba
We construct a gravastar configuration within the Shtanov-Sahni (SS) braneworld scenario, characterized by a timelike extra dimension and negative brane tension. Unlike classical b…
A model-independent measurement of the Hubble constant from gravitational-wave standard sirens and electromagnetic observations
Gaurav N. Gadbail, Kazuharu Bamba
The Hubble tension is one of the most significant challenges in modern cosmology. Developing new approaches to estimate the Hubble constant is therefore crucial, and in this work,…
Physical Features of Geometrically Deformed Anisotropic Charged Three-dimensional BTZ Black Holes
Z. Yousaf, Kazuharu Bamba, Mansoor Alshehri +2
This work employs the minimal geometric deformation decoupling scheme to derive interior stellar solutions in the background of an electrically charged BTZ ansatz as a seed metric…