Angular smoothing and spatial diffusion from the Feynman path integral representation of radiative transfer

作者：Tessendorf Jerry^*

来源：Journal of Quantitative Spectroscopy and Radiative Transfer, 2011, 112(4): 751-760.

DOI：10.1016/j.jqsrt.2010.11.004

• Feynman path integral
• Diffusion
• Stationary phase
• Steepest descents
• Propagation kernel
• Computer graphics

The propagation kernel for time dependent radiative transfer is represented by a Feynman path integral (FPI). The FPI is approximately evaluated in the spatial-Fourier domain. Spatial diffusion is exhibited in the kernel when the approximations lead to a Gaussian dependence on the Fourier domain wave vector. The approximations provide an explicit expression for the diffusion matrix. They also provide an asymptotic criterion for the self-consistency of the diffusion approximation. The criterion is weakly violated in the limit of large numbers of scattering lengths. Additional expansion of higher-order terms may resolve whether this weak violation is significant.

• 出版日期2011-3