Function proca_equation_kernel 

pub fn proca_equation_kernel(
    field_manifold: &Manifold<f64>,
    potential_manifold: &Manifold<f64>,
    mass: f64,
) -> Result<CausalTensor<f64>, PhysicsError>

Calculates the Proca Equation (Massive Electromagnetism): $\delta F + m^2 A = J$.

Computes the source current density 1-form $J$ given the field $F$, potential $A$, and mass $m$.

Arguments

• field_manifold - Manifold containing the field 2-form $F$ (maxwell gradient).
• potential_manifold - Manifold containing the potential 1-form $A$.
• mass - Mass of the photon $m$ (typically $\approx 0$, but $>0$ in Proca theory).

Returns

• Result<CausalTensor<f64>, PhysicsError> - Current density 1-form $J$.