DOI:
10.1038/s41598-022-19836-8
IAA authors:
Arrechea, Julio;Barceló, Carlos
Authors:
Arrechea, Julio;Barceló, Carlos;Carballo-Rubio, Raúl;Garay, Luis J.
Abstract:
We present strong evidence that semiclassical gravity can give place to self-consistent ultracompact stars beyond the Buchdahl limit. We integrate the semiclassical equations of (spherically symmetric) stellar equilibrium for a constant-density classical fluid. The semiclassical contribution is modelled by a quantum massless scalar field in the only static vacuum state compatible with asymptotic flatness (Boulware vacuum). The Renormalized Stress-Energy Tensor (RSET) is firstly approximated by the analytic Polyakov approximation. This already reveals a crucial difference with respect to purely classical solutions: stars with compactness close to that of a black hole exhibit bounded pressures and curvatures up to a very small central core compared with the star radius. This suggests that a more refined approximation to the RSET at the core may give rise to strictly regular configurations. Following this suggestion, we prove that a minimal deformation of the Polyakov approximation inside the central core is sufficient to produce regular ultracompact stellar configurations.
URL:
https://ui.adsabs.harvard.edu/#abs/2022NatSR..1215958A/abstract
Keywords:
General Relativity and Quantum Cosmology;High Energy Physics - Theory