Testing Loop Quantum Gravity from Observational Consequences of Nonsingular Rotating Black Holes.

Area of Science:

• Theoretical physics
• Quantum gravity
• Astrophysics

Background:

• Loop quantum gravity (LQG) lacks realistic rotating black hole models, impeding observational verification.
• Natural black holes are rotating, making their absence in LQG a significant gap.

Purpose of the Study:

• To construct a rotating, nonsingular black hole solution within the LQG framework.
• To enable observational testing of LQG using black hole properties.

Main Methods:

• Utilized a nonrotating LQG black hole as a seed metric.
• Applied the revised Newman-Janis algorithm to generate a rotating spacetime.
• Analyzed the parameter space to identify different physical regimes.

Main Results:

• Developed a nonsingular rotating black hole solution that asymptotically approaches the Kerr metric.
• Identified three possible configurations: a wormhole, a black hole with a spacelike transition surface, or one with a timelike transition region.
• Demonstrated that LQG fundamental parameters can be constrained by the observed shadow of the black hole.

Conclusions:

• The derived rotating LQG black hole model captures universal features of nonsingular black holes.
• The causal structure is robustly linked to the spacelike transition surface of the seed metric.
• This work paves the way for observational constraints on LQG through black hole astrophysics.