2023/12/03 by Shou-Long Li, Shoulong Li, Li, Shoulong +11 · 4 citations
Engineering · Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Binary black hole #Black hole (networking) #Field (mathematics) #Gamma-ray burst progenitors #Gamma-ray bursts and supernovae #General relativity #Geophysics and Sensor Technology #Gravitation #Gravitational collapse #Gravitational field #Gravitational wave #Neutron star #Physics #Pulsars and Gravitational Waves Research #Star (game theory) #Stars #Stellar black hole #Strong gravity #Theoretical physics #Universe
paper · pdf · doi:10.1103/3c9w-xc9l
published in Physical review. D/Physical review. D. 114(2) (American Physical Society)
openalex created_date 2023/12/06 · openalex publication_date 2026/06/26 · openalex updated_date 2026/08/04
Probing gravity in its strongest regime is a central goal of modern physics, as the nature of the most compact objects reflects fundamental aspects of Einstein's theory of general relativity (GR). In GR, black holes are regarded as the most compact objects in the Universe. Here, for the first time, we demonstrate that stable stellar configurations more compact than black holes can arise when neutron-star equations of state are embedded in quasi-topological gravity, a class of higher-curvature extensions of GR. We construct such ultra-compact stars, analyze their macroscopic properties, and establish their stability against radial perturbations, confirming their physical plausibility. We further identify potential observational signatures to distinguish these stars from black holes, most notably gravitational-wave echoes whose detectability could provide direct evidence of physics beyond Einstein's GR in the strong-field regime.