Exploring Quantum Corners: How Curved Momentum Space Shapes BTZ Black Holes

Abstract

Planck-scale signatures of quantum gravity may emerge semiclassically not only through modifications of spacetime geometry but also through the geometry of momentum space. In this work, we develop a $(2+1)$-dimensional framework in which a noncommutative algebra of spacetime localization operators reconstructs a locally anti-de Sitter momentum-space geometry in the classical limit. The resulting momentum-space curvature deforms the phase-space structure, modifies particle kinematics, and leads to a finite renormalization of the particle mass. Using an effective configuration-space action, we derive the corresponding stress-energy tensor that consistently sources the classical Einstein equations without modifying the gravitational dynamics. The resulting spacetime is a deformed BTZ black hole whose conserved mass, horizon radius, Hawking temperature, and Bekenstein-Hawking entropy acquire finite Planck-scale corrections. We further investigate Hawking radiation using the Hamilton-Jacobi tunneling formalism and show that the return time of an emitted massless particle receives two distinct contributions: a geometric correction induced by curved momentum space and a dynamical correction arising from Hawking backreaction. Remarkably, the null geodesic equations remain unchanged, indicating that the observable effects originate entirely from the deformation of the effective spacetime geometry rather than from modifications of particle trajectories. These results provide a concrete semiclassical mechanism through which quantum kinematics encoded in curved momentum space can generate observable gravitational phenomena without requiring a quantization of spacetime itself, thereby offering a phenomenological bridge between quantum geometry and black-hole physics.