3 papers
gr-qc2026
The bending of a straight line
Zonghai Li, Xiao-Jun Gao
In gravitational lensing under the weak-field approximation, the usual viewpoint is that light bending measures how a ray deviates from a straight line in Euclidean space. In this…
gr-qc2025
From Spray to Metric: The Geometric Construction of the Jacobi Metric
Zonghai Li
This paper develops a systematic approach to the geometrization of dynamics from the viewpoint of the geodesic equation. The method promotes a semispray to a spray through the impo…
gr-qc2025
Gravitational Lensing Using Werner's Method in Cartesian-like Coordinates
Zonghai Li
The Gibbons-Werner method for calculating deflection angles using the Gauss-Bonnet theorem and optical/Jacobi metric has become widely popular in recent years. Werner extended this…