7 papers
A universal lower bound on the photon sphere radius in higher-dimensional black holes
Yong Song, Jiaqi Fu, Yiting Cen
The photon sphere, a hypersurface of circular null geodesics, plays a fundamental role in characterizing black hole spacetimes, influencing phenomena such as black hole shadows, gr…
Bounds on the photon sphere radius for spherically symmetric black holes in n-dimensional Einstein gravity
Yong Song, Jiaqi Fu, Yiting Cen
The photon sphere, a hypersurface of null circular geodesics, plays a fundamental role in characterizing black hole spacetimes, influencing phenomena such as black hole shadows, gr…
Robust topological invariants of timelike circular orbits for spinning test particles in black hole spacetimes
Yong Song, Jiaqi Fu, Yiting Cen
The spin-curvature coupling in the Mathisson-Papapetrou-Dixon (MPD) formalism induces non-geodesic motion, shifting the orbital parameters of spinning test particles in black hole…
The existence and upper bound for stable photon spheres in static spherically symmetric black holes
Yong Song, Jiaqi Fu, Yiting Cen
In this work, we establish the existence conditions and a universal upper bound on the radius of stable photon spheres (SPS) outside the event horizons of static, spherically symme…
From quasi-local definitions to a dynamical potential: A unified framework for evolving circular orbits in dynamical spacetimes
Yong Song
The study of circular orbits is fundamental in gravitational physics, yet their definition in dynamical spacetimes remains challenging due to the lack of temporal symmetry. In this…
Upper bound on the radius of the innermost stable circular orbit of black holes
Yiting Cen, Yong Song
In this work, we investigate a universal upper bound on the radius of the innermost stable circular orbit (ISCOs) for massive particles in static, spherically symmetric, and asympt…