Exploring a Novel Feature of Ellis Spacetime: Insights into Scalar Field Dynamics

TL;DR

This paper investigates the effects of an external scalar field on particle dynamics, stability, and perturbations in Ellis spacetime, providing analytical and numerical insights into wormhole physics and observational constraints.

Contribution

It introduces new analytical solutions for particle oscillations, explores the scalar and gravitational perturbations, and constrains wormhole parameters using observational data.

Findings

Scalar field affects ISCO position non-linearly.

Analytical expressions for radial and angular oscillations are derived.

Numerical solutions for perturbation equations are provided.

Abstract

We have studied neutral and charged massive particles dynamics in Ellis spacetime in the presence of the external scalar field. Focusing on the circular motion of massive particles, the impact of an external scalar field on the Innermost Stable Circular Orbit (ISCO) position is analyzed, revealing a non-linear relationship with the scalar field parameter. Perturbation techniques are employed to investigate oscillatory motion near stable orbits in the Ellis spacetime, yielding analytical expressions for radial and angular oscillations. The throat of the wormhole has been constrained by comparing theoretical and observational results for fundamental frequencies of particles from quasars. Finally, scalar and gravitational perturbations in the Ellis spacetime have been studied. It is shown that the equation for the scalar profile function is fully independent from the tensor functions, and the solution can be represented in terms of the confluent Heun function. However, it has been shown that equations for the tensor profile functions strongly depend on the scalar profile functions in the Ellis spacetime, and they are reduced to the Regge-Wheeler-Zerilli equation. Finally, numerical solutions to the Regge-Wheeler-Zerilli equation for the radial functions in the Ellis spacetime have been presented.