Killing versus branching: Unexplored facets of diffusive relaxation

We analyze the relaxation dynamics of Feynman-Kac path integral kernel functions in terms of branching diffusion processes with killing. This sheds new light on the admissible path-wise description of the relaxation to equilibrium for conditioned Brownian motions, and diffusion processes with absorbing boundaries, where Feynman-Kac kernels appear as the building blocks of inferred transition probability density functions.