Regular Black Holes Show Stronger Magnetic Charge, Hawking Radiation Studied

Regular magnetically charged black holes, arising from coupled general relativity and nonlinear electrodynamics, exhibit enhanced regularity and Hawking temperatures modified by the generalised uncertainty principle. Light deflection, analysed via the Gauss-Bonnet theorem, demonstrates charge-dependent behaviour, while Keplerian motion reveals charge-sensitive quasi-periodic oscillations and Joule-Thomson expansion indicates cooling with increasing charge.

The nature of black holes continues to fascinate physicists, and recent research explores solutions beyond the standard models, investigating how modifications to established theories might affect their properties and observational signatures. Ekrem Aydiner, from Princeton University, and Ekrem Aydiner, from Istanbul University, alongside Erdem Sucu and Izzet Sakallı from Eastern Mediterranean University, present a detailed analysis in their article, ‘Regular Magnetically Charged Black Holes from Nonlinear Electrodynamics: Thermodynamics, Light Deflection, and Orbital Dynamics’. The study examines the behaviour of regular black holes incorporating magnetic charge and arising from nonlinear electrodynamics, a theoretical framework extending standard electromagnetism, and investigates their thermodynamic properties, how they deflect light, and the dynamics of objects orbiting them. The research utilises established techniques such as the tunneling framework to calculate Hawking temperature, the Gauss-Bonnet theorem to analyse light deflection, and Keplerian motion analysis to understand orbital behaviour, offering insights relevant to gravitational lensing and X-ray astronomy.

Regular Magnetic Black Holes: Towards Resolution of Singularities and Observational Signatures

General relativity, proposed by Albert Einstein, predicts the existence of black holes as regions of spacetime exhibiting gravitational fields so intense that nothing, not even light, can escape. Classical black hole solutions, however, contain a singularity at their centre, a point of infinite density and curvature where the established laws of physics break down, presenting a fundamental challenge for theoretical physics. This prompts ongoing investigation into alternative black hole models that resolve this singularity and offer a more complete description of these enigmatic objects.

Regular black holes represent a class of solutions that maintain the essential characteristics of classical black holes while avoiding the central singularity, offering a potentially more physically realistic model. These models achieve regularity by modifying Einstein’s field equations or introducing exotic matter with specific energy-momentum properties, counteracting gravitational collapse and creating a smooth spacetime geometry. Nonlinear electrodynamics (NED) provides a compelling framework for constructing these regular black hole solutions, extending Maxwell’s equations to account for strong electromagnetic fields and potentially resolving the singularity problem through the stress-energy tensor of the nonlinear electromagnetic field.

Magnetic black holes, specifically those arising from NED, are of particular interest due to their enhanced stability and preservation of electromagnetic duality, offering advantages over electrically charged counterparts. Unlike electrically charged black holes, magnetic charges are not readily neutralised in astrophysical environments, making them more plausible candidates for observation and study. Furthermore, the magnetic field significantly influences the spacetime geometry, affecting light deflection and orbital dynamics around the black hole.

Researchers are currently investigating regular magnetically charged black holes, theoretical constructs arising from the coupling of general relativity with nonlinear electrodynamics, to understand their unique properties and potential observational signatures. Unlike traditional black holes described by the Schwarzschild or Kerr metrics, these regular black holes possess a modified spacetime geometry that avoids the singularity at the centre, offering a more physically plausible model and opening new avenues for theoretical exploration.

A key aspect of this research involves calculating the Hawking temperature, incorporating corrections from the generalized uncertainty principle, a modification of quantum mechanics at very small scales, and revealing a decrease in temperature with increasing charge. The study employs the tunneling framework, a quantum mechanical method, to derive this temperature, providing insights into the quantum behaviour of these objects and their interaction with the surrounding environment. The analysis of light deflection around these black holes utilises the Gauss-Bonnet theorem, a mathematical tool that relates the geometry of a surface to its total curvature, revealing charge-dependent behaviour where larger charges can lead to negative deflection angles.

Researchers account for plasma effects, modelling the surrounding environment as a refractive medium that further modifies the path of light, providing a more realistic picture of how light interacts with these objects. The orbital dynamics around these regular black holes are examined through Keplerian motion analysis, which describes the motion of objects in elliptical orbits, revealing that the angular velocity of orbiting objects exhibits charge-sensitive maxima. These oscillations potentially relate to quasi-periodic oscillations observed in accretion disks surrounding black holes, offering a means of probing the properties of the central black hole and its surrounding environment.

Regular magnetically charged black holes (NRCBHs), arising from the coupling of nonlinear electrodynamics (NED) to general relativity, exhibit complete regularity at their origin while maintaining asymptotic flatness, offering a more physically realistic model. Researchers currently investigate these objects to understand their properties, light deflection, and orbital dynamics, and to compare their behaviour with that of traditional black holes. The NRCBH metric function achieves this regularity, with the extremal magnetic charge limit reaching a value significantly exceeding that of the Reissner-Nordström black hole, allowing for stronger electromagnetic effects.

Analysis of weak light deflection utilises the Gauss-Bonnet theorem (GBT), revealing charge-dependent behaviour where large charge values induce negative deflection angles due to electromagnetic repulsion, and providing insights into the interaction of light with these objects. The refractive index, accounting for plasma effects, further modifies the deflection of light around these black holes, offering a more realistic picture of light propagation in these environments.

Keplerian motion analysis demonstrates that the angular velocity of orbiting particles exhibits charge-sensitive maxima, potentially linking to quasi-periodic oscillations (QPOs) observed in accretion disks surrounding black holes, and providing a means of probing the strong gravitational field near the event horizon. Furthermore, investigations into the Joule-Thomson expansion (JTE) properties reveal that the coefficient indicates cooling behaviour for higher charges and larger event horizons, providing insights into the thermodynamic properties of matter in extreme gravitational environments.

These findings collectively provide comprehensive insights into the observational signatures of NRCBHs, with implications for gravitational lensing studies, X-ray astronomy, and stringent tests of nonlinear electromagnetic theories within strong gravitational fields. The research establishes a framework for interpreting observational data and distinguishing NRCBHs from other black hole models, furthering our understanding of these exotic objects and the fundamental laws governing the universe.

This research presents a comprehensive investigation into regular magnetically charged black holes (NRCBHs) derived from nonlinear electrodynamics (NED) coupled with general relativity, offering a more complete picture of these exotic objects. The study establishes that these NRCBHs maintain complete regularity at their origin while exhibiting asymptotic flatness, with an extremal magnetic charge limit notably exceeding that of the Reissner-Nordström metric, allowing for stronger electromagnetic effects. Calculations demonstrate a Hawking temperature derived via the tunneling framework, incorporating corrections from the generalized uncertainty principle (GUP), which yields a temperature proportional to the inverse of the event horizon, and providing insights into the thermal properties of these objects.

Analysis of light deflection employs the Gauss-Bonnet theorem (GBT), revealing a charge-dependent behaviour where substantial charge values induce negative deflection angles attributable to electromagnetic repulsion, and providing insights into the interaction of light with these objects. The research further models plasma effects, demonstrating their modification of deflection angles through the application of a refractive index, and providing a more realistic picture of light propagation in these environments. Keplerian motion analysis indicates that the angular velocity exhibits charge-sensitive maxima, potentially linking to quasi-periodic oscillations (QPOs) observed in accretion disks surrounding black holes, and providing a means of probing the strong gravitational field near the event horizon.

Joule-Thomson expansion (JTE) properties are also examined, revealing that the coefficient, indicative of cooling behaviour, increases with higher charges and larger event horizons, and providing insights into the thermodynamic properties of matter in extreme gravitational environments. These findings collectively provide detailed insights into the potential observational signatures of NRCBHs, with implications for gravitational lensing studies, X-ray astronomy, and stringent tests of nonlinear electromagnetic theories within strong gravitational fields.