Calculation record
Full spatial second variation of the linked normal compression.
Only the angular mean of the second mode derivative is needed for the
radial diagonal polarization and adjacent hopping entries. Nonlinear
texture and connection variations are included, not frozen.
Research context
- The complete second spatial response and its rotation identity
The second projected polarization is fixed by the normal Berry curvature; the actual second geometry and moving modes also determine the adjacent hopping Hessian without freezing the spatial coefficients.
Interpret numerical checks within the assumptions and limitations documented in these notes.