482 papers
This paper investigates the shadows of rotating traversable wormholes in the Teo class, demonstrating that a variable redshift parameter induces a universal critical value leading to cuspy structures and revealing four distinct shadow morphologies that could serve as observational diagnostics for compact objects.
This paper extends the principle of relativity to finite-mass quantum observers by establishing operational requirements for transition amplitude equivalence and the inaccessibility of an observer's own motion state, resulting in a fully relative formulation of quantum mechanics with observer-dependent Hilbert spaces, novel uncertainty relations, and experimentally testable signatures.
This paper extends the Bemfica-Disconzi-Noronha-Kovtun (BDNK) first-order dissipative relativistic hydrodynamics model to include a full first-order charge current with out-of-equilibrium corrections, demonstrating that this inclusion ensures a strongly hyperbolic, causal, and stable system coupled to Einstein's equations without requiring additional frame restrictions.
This paper investigates a diverse spectrum of Euclidean gravitational saddles, including wormholes and oscillatory solutions, within Einstein-Scalar-Maxwell models to identify phase transitions, demonstrate how potential flat directions are stabilized, and estimate the probabilities of various cosmological outcomes by analytically continuing these backgrounds to Lorentzian FLRW universes.
This paper proposes group entropies as a unifying framework that defines universality classes of extensive entropies for strongly correlated systems, successfully deriving consistent thermodynamic laws and demonstrating that black holes naturally exhibit negative specific heat within this formalism.
This study employs the gravitational decoupling method within Rastall theory to derive and analyze two novel asymptotically flat Bardeen black hole solutions, confirming their thermodynamic stability and acceptable physical behavior despite violations of energy bounds.
This paper proposes that dark energy arises not from vacuum fluctuations but as an effective entanglement energy between our universe and a time-reversed mirror sector, offering a unified framework where vacuum contributions cancel under a global zero-energy condition and the observed dark energy density is determined by boundary conditions at the cosmological event horizon.
This paper investigates the Blandford-Znajek mechanism in Kerr-Sen black holes using perturbation theory to show that while the dilaton parameter enhances energy extraction power and radiative efficiency compared to standard Kerr black holes, observational data from binary systems still favors the Kerr model.
This paper introduces a new local four-velocity gauge-like symmetry for imperfect fluids with vorticity, utilizing a tetrad formulation to construct invariant stress-energy tensors and demonstrating their application in simplifying neutron star models.
This paper investigates the limit of Gauss-Bonnet gravity coupled with quintessence, deriving exact black hole solutions that exhibit unique horizon behaviors, stable phantom-like photon orbits, and thermodynamic stability leading to stable remnants, thereby highlighting the profound influence of quintessential matter on lower-dimensional gravitational physics.
The paper proves that for spherically symmetric hairy black holes satisfying the weak energy condition, the ratio of the shadow radius to the horizon radius is bounded from below by $3\sqrt{3}/2$, a limit that is saturated by the Schwarzschild black hole.
By employing a relaxed BF-BB parametrisation of 4D gravity, this paper demonstrates that the theory possesses Chern-Simons-like phase spaces and Kac-Moody algebras on codimension 2 and 3 surfaces, respectively, governed by a Maxwell gauge algebra that yields an off-shell commutative spin connection and a noncommutative corner metric.
This paper investigates how non-Bunch-Davies initial conditions affect the gravitational production of relic particles, demonstrating that while the impact is negligible for conformally coupled fields, it significantly alters the abundance and spectrum of other particles like spin-1 longitudinal modes, thereby allowing for viable dark matter production across a wide range of masses.
This paper investigates cosmology in gravity by demonstrating that a thick brane's embedding in a five-dimensional bulk naturally generates an effective cosmological constant and accelerated expansion without a fundamental brane constant, offering a geometric explanation for cosmic acceleration and the smallness of the observed cosmological constant.
This paper derives slowly rotating charged BTZ black hole solutions in 2+1 dimensional Palatini Chern-Simons gravity by employing a metric-affine formulation and a perturbative approach around a non-rotating background, demonstrating that specific parameter constraints are required to ensure stable perturbations that yield a rotating solution with constant angular momentum and magnetic field at the horizon.
This paper proposes utilizing the line-of-sight shear of strong gravitational lenses detected in Stage-IV surveys as a new cosmological probe, demonstrating through analytical derivations and covariance analysis that this approach significantly enhances the standard $3\times 26\times 2$pt scheme with high signal-to-noise ratio and potential for mitigating systematic errors.
This review explores how multi-messenger astronomy and diverse observational data across various scales constrain and probe extensions to the Standard Model and General Relativity, including dark matter candidates and modified gravity theories, to illuminate the nature of the dark sector.
This paper investigates the physical properties of accelerating Bertotti-Robinson black holes in a uniform magnetic field by analyzing their Hawking temperature, geodesic motion, orbital stability, photon sphere characteristics, and energy emission rates to determine how the acceleration and magnetic field parameters influence these phenomena.
This paper presents the first observational constraints on Luciano-Saridakis entropic cosmology using combined background data, demonstrating that the model provides a statistically robust fit to current observations and offers a viable extension to the standard CDM model with the potential to alleviate the Hubble tension.
This paper establishes a correspondence between the Extended Uncertainty Principle (EUP) and the Schwarzschild black hole metric to demonstrate that while the event horizon remains unchanged, increasing EUP parameters expand the photon sphere but shrink the shadow size, thereby allowing observational data from Sgr A* to constrain EUP parameters.