Description
Quantum gravity candidate theories are expected to resolve the curvature singularities of classical general relativity. In the absence of a complete theory, regular ultracompact objects provide useful effective models of nonsingular compact geometries, including both regular black holes and horizonless configurations. However, many such metrics are introduced phenomenologically, making it unclear which features follow from a constrained dynamical framework.
We present a unified construction of static, spherically symmetric regular ultracompact objects from polymerized vacuum dynamics inspired by loop quantum gravity. Starting from the Lemaître–Tolman–Bondi description of gravitational collapse, the absence of gravitational-wave degrees of freedom in spherical symmetry and the non-propagating character of the relational dust clock allow the vacuum dynamics to decompose into independent radial shells. This constrains the effective Hamiltonian and leads to a universal reconstruction of the static metric. The resulting solutions satisfy a Birkhoff-type property: once the polymerized vacuum Hamiltonian is specified, the static geometry is fixed.
The framework yields a broad class of nonsingular geometries, including regular black holes with de Sitter or anti-de Sitter cores, horizonless counterparts, and inner-extremal black holes with degenerate inner horizons. I will emphasize how polymerization controls the global structure of the solution, how different core geometries arise, and what distinguishes the black hole and horizonless branches.
Based on:
1) H. Liu and I. Soranidis, Regular ultracompact objects with anti-de Sitter cores as polymerized vacuum solutions, arXiv:2604.27880
2) H. Liu and I. Soranidis, Probing mass inflation in polymerized vacuum regular black holes via colliding null shells, arXiv:2604.27897
| I am the presenting author | Yes |
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