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From the 1 of 5 linked papers with an AI index.

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5 papers

gr-qc2026

Bounds on the radius of outermost photon sphere and black hole shadow in -dimensional Einstein gravity

Jiaqi Fu, Yong Song

The paper derives model‑independent upper and lower bounds on the radius of the outermost photon sphere and the black hole shadow for static, spherically symmetric, asymptotically…

gr-qc2026

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…

gr-qc2026

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…

gr-qc2026

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…

gr-qc2025

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…