Effects of spontaneous Lorentz Symmetry breaking on Letelier-AdS charged black holes within Kalb-Ramond gravity

TL;DR

This paper explores how spontaneous Lorentz symmetry breaking affects the geometry and observable features of charged AdS black holes in Kalb-Ramond gravity, analyzing photon and particle dynamics, BH shadows, and QPOs.

Contribution

It introduces a detailed analysis of photon and test particle motion in Lorentz symmetry breaking AdS black holes with Kalb-Ramond fields, connecting theoretical models with observational data.

Findings

The BH shadow size and shape are influenced by the CoS and KR parameters.

Constraints on CoS and KR parameters are derived from EHT observations of M87* and Sgr A*.

The presence of these fields modifies fundamental frequencies of QPOs, affecting potential gravitational wave signals.

Abstract

In this study, we investigate the geodesic motion of massless particles -- specifically photons -- in the spacetime of a charged anti-de Sitter (AdS) black hole (BH) surrounded by a cloud of strings (CoS) within the framework of Kalb-Ramond (KR) gravity. We analyze the effective potential that governs photon trajectories, explore the properties and location of the photon sphere (PS), and examine the effective radial force acting on photons. The resulting BH shadow is also studied, highlighting the roles of both the CoS parameter $\alpha$ and the KR field parameter $\ell$ in shaping its geometry. We constrain these parameters using observational data from M87* and Sgr A* obtained by the Event Horizon Telescope (EHT). Furthermore, we extend our investigation to the motion of neutral test particles in the same gravitational background. By examining the impact of the CoS and KR field, we show how these additional fields modify the dynamics relative to standard charged BH scenarios. Finally, we study the fundamental frequencies associated with quasiperiodic oscillations (QPOs) of test particles, demonstrating how these frequencies are affected by the presence of the CoS and KR field. Our results reveal the rich structure of AdS-BH spacetimes influenced by string clouds and antisymmetric tensor fields, with potential observational consequences in gravitational wave and BH imaging astronomy.