arXiv subjects

S. K. Narasimhamurthy

Publications and source records attributed to S. K. Narasimhamurthy.

9 recordsLinked to original sources

arXiv2025

Finslerian Wormholes in squared trace gravity

We investigate traversable wormholes in squared-trace extended gravity within the framework of Finsler-Randers geometry equipped with the Barthel connection. The Einstein-Hilbert action is modified by terms involving the trace of the energy-momentum tensor and its square, generating effective anisotropies through matter-curvature coupling. The resulting field equations are studied under barotropic equations of state with exponential and power-law shape functions. Finslerian anisotropy introduces novel pressure dynamics that enable the classical energy conditions to be satisfied in specific parameter domains. Our analysis shows that the Barthel connection significantly extends the parameter space for non-exotic, physically viable wormholes compared to purely Riemannian models. These findings suggest that Finslerian modifications provide a powerful mechanism for realizing realistic wormhole structures, offering new perspectives on anisotropic and geometrically enriched space-time configurations in extended gravity.

gr-qc↗

arXiv2024

Special Finsler spaces admitting a semi-concurrent vector field

The main objective of this paper is to study semi-concurrent vector fields on a Finsler manifold. We show that the quasi-$C$-reducible Finsler space, $C3$-like Finsler space, $C^{h}$-recurrent Finsler space, and $P2$-like Finsler space are equivalent to Riemannian if they admit a semi-concurrent vector field. Further, we prove the necessary and sufficient condition for a Finsler space satisfying $C$-conformal condition to become Riemannian.

math.DG↗

arXiv2024

Cosmological tests of the dark energy models in Finsler-Randers Space-time

The Finsler-Randers space-time offers a novel perspective on cosmic dynamics, departing from the constraints of General Relativity. This paper thoroughly investigates two dark energy models resulting from the parametrization of $H$ within this geometric framework. We have conducted some geometrical and physical analysis of the dark energy models in Finslerian geometry. First, We have derived the field equations governing the universe's evolution within the Finsler-Randers formalism, incorporating the presence of dark energy. Through this, we explore its implications on cosmological phenomena, including cosmic expansion, late-time behavior of the universe, cosmological phase transition, and a few more. Also, we employ observational data such as Cosmic Chronometer, Supernovae, Gamma-Ray Bursts, Quasar, and baryon acoustic oscillations to constrain the parameters associated with dark energy in the Finsler-Randers universe. Comparing theoretical predictions with empirical observations, we assess the model viability and discern any deviations from the standard $Λ$CDM cosmology. Our findings offer intriguing insights into the nature of dark energy within this alternative gravitational framework, providing a deeper understanding of its role in shaping cosmic evolution. The implications of our results extend to fundamental cosmology, hinting at new avenues for research to unravel the mysteries surrounding dark energy and the geometric structure of the universe within non-standard gravitational theories.

gr-qc↗

arXiv2024

Black Hole Solutions with Constant Ricci Scalar in a Model of Finsler Gravity

Ricci scalar being zero is equivalent to the vacuum field equation in Finsler space-time. The Schwarzschild metric can be concluded from the field equation's solution if the space-time conserves spherical symmetry. This research aims to investigate Finslerian Schwarzschild-de Sitter space-time. Recent studies based on Finslerian space-time geometric models are becoming more prevalent because the local anisotropic structure of space-time influences the gravitational field and gives rise to modified cosmological relations. We suggest a gravitational field equation with a non-zero cosmological constant in Finslerian geometry and apprehend that the presented Finslerian gravitational field equation corresponds to the non-zero Ricci scalar. In Finsler geometry, the peer of spherical symmetry is the Finslerian sphere. Assuming space-time to conserve the "Finslerian sphere" symmetry, the counterpart of the Riemannian sphere (Finslerian sphere) must have a constant flag curvature ($λ$). It is demonstrated that the Finslerian covariant derivative of the geometric part of the gravitational field equation is preserved under a condition using the Chern connection. According to the string theory, string clouds can be defined as a pool of strings made due to symmetry breaking in the universe's early stages. We find that for $λ\neq1$, this solution resembles a black hole surrounded by a cloud of strings. Furthermore, we investigate null and time-like geodesics for $λ=1$. In this regard, the photon geodesics are obtained that are the closest paths to the photon sphere of the first photons visible at the black hole shadow limit. Also, circular orbit conditions are obtained for the effective potential.

gr-qc↗

arXiv2024

Finslerian wormhole solution in the framework of modified gravity

This article investigates the properties of a wormhole model in a specific gravity theory, namely $f(Ric, T)=Ric+2λT$. The wormhole solution is analyzed using an exponential shape function. The study examines various parameters, such as density, radial pressure, transverse pressure, equation-of-state parameters, and energy conditions, within the framework of deformed gravity. The research emphasizes the influence of the parameter $λ$ on energy condition violations and the equilibrium state of the Finslerian wormhole solution. These effects are attributed to anisotropic and hydrostatic forces present in modified gravity. The study demonstrates that the gravity model effectively captures the characteristics of wormholes within the Finslerian space-time. Additionally, the identified features of the wormhole are utilized to visualize its structure by creating a three-dimensional representation of the embedded surface. In summary, this research contributes to understanding wormholes in modified gravity theories, highlighting the importance of the parameter $λ$ in determining their behavior and properties.

gr-qc↗

arXiv2024

Physical viability of traversable Finslerian wormholes with traceless fluid under conformal symmetry

The current study explores the novel potential of traversable wormhole solutions within the framework of Finsler geometry, incorporating conformal symmetry alongside traceless fluid dynamics. Using the Conformal Killing vector approach, we have discussed the wormholes based on traceless fluid within the intriguing framework of Finsler geometry. The field equations and the associated conformal factor are obtained specifically under the condition of conformal motion in Finsler geometry. Furthermore, we have successfully derived and examined the shape function, considering a range of values for the Finslerian parameter $λ$. Our investigation extends to fundamental physical characteristics such as proper radial distance, active mass function, and total gravitational energy, aiming to understand their influence on the traversability of the wormhole. The observation of energy condition violations provides evidence for the exotic matter's presence near the throat, reinforcing the assertion of the Finslerian wormhole's traversability.

gr-qc↗

arXiv2024

Traversable wormholes in Finsler geometry under conformal motion

This paper aims to investigate the possibility of physically achievable new wormhole solutions within the context of Finsler geometry by focusing on conformal motion. For this purpose, we study the barotropic linear equation of state (EoS). We scrutinized their geometric features within the EoS model, which includes baryonic and non-baryonic matter. Through derived field equations, shape functions adhering to critical criteria governed by the Finsler parameter $γ$ are explored. By evaluating energy conditions, violations are found, which indicate the potential presence of exotic matter necessary for traversable wormholes. Notably, violations of energy conditions signify the plausibility of traversable wormholes within the conformally transformed Finslerian space observed in both baryonic and non-baryonic scenarios. Additionally, anisotropy exploration uncovers repulsive geometric characteristics within these wormholes.

gr-qc↗

arXiv2022

Static conformal elastic solution of Einstein's field equations

In this paper, we study new exact solutions of Einstein's field equations with the motivation of the relativistic elasticity theory. We construct the static conformal elastic solution by applying conformal transformations to the Reissner-Nordström-de Sitter solution. The conformal factors for static space-time structure with an elastic matter are obtained. Further, we analyze the viability of energy conditions. And also discuss the matching problem with the exterior space-time.

gr-qc↗

arXiv2020

The gravitational field of the SdS space-time

The goal of this paper is to study SdS space-time and its gravitational field with consideration of the canonical form and invariants of the curvature tensor. The characteristic of $λ$-tensor identifies the type of gravitational field. Gaussian curvature quantities enunciated in terms of curvature invariants.

gr-qc↗