Thermodynamics and shadow of Simpson-Visser black hole with phantom global monopoles

TL;DR

This paper studies the thermodynamics and shadow of a Simpson-Visser black hole with a phantom global monopole, revealing how parameters like the bounce parameter and monopole influence stability, photon sphere, and observational features.

Contribution

It provides analytical analysis of the black hole's thermodynamics and shadow, incorporating the effects of a phantom global monopole and bounce parameter, which are novel aspects.

Findings

Small-horizon configurations are thermodynamically stable but not globally favored.

Photon sphere radius depends on bounce parameter and symmetry breaking scale.

Increasing symmetry breaking scale enlarges photon sphere in normal monopoles but reduces it in phantom monopoles.

Abstract

We investigate the thermodynamics and shadow of a non-rotating Simpson Visser black hole with a phantom global monopole. The model is governed by three parameters: the coupling constant $\xi$, the energy scale of symmetry breaking $\eta$, and the bounce parameter $a$, which jointly influence horizon structure and observational signatures. Using specific heat and free-energy analysis, we show that small-horizon configurations are locally thermodynamically stable but never globally favored. Analytical solutions of null geodesics reveal that the photon sphere radius depends on the bounce parameter $a$ and the energy scale of symmetry breaking $\eta$, while the critical impact parameter is still unaffected by $a$. Moreover, the photon sphere radius and critical impact parameter, showing that increasing $\eta$ enlarges both quantities for an ordinary global monopole, while reducing them in the phantom case. Our results highlight how the bounce parameter and phantom global monopole significantly alter the black hole's physical and geometric properties.