Parallel transport on a sphere
What you are seeing: a "Beltrami" spherical triangle on the unit sphere with one vertex at the north pole and the other two on a colatitude circle, separated by longitude . Parallel transport of any vector around the triangle returns it rotated by the enclosed solid angle . This is Gauss-Bonnet on the sphere of constant curvature : the angle excess equals the integrated curvature, which is just the area on the unit sphere.
For the full hemisphere (, ) the holonomy is : a full rotation. For a quarter octant () the holonomy is . For tiny triangles the holonomy is just the area, vanishing as .
Surface
alpha (deg)60
beta (deg)90
Omega (sr):0
A + B + C - pi:0
00WHAT TO TRY
- Switch between the sphere, cone, and cylinder and compare the holonomy each loop accumulates.
- Drag the canvas to rotate; on the cone, narrow the half-angle to widen the apex deficit.