It is shown that mass-parameter-dependent solutions of the imaginary-time magnetic relativistic Schrödinger equations converge as functionals of Lévy processes represented by stochastic integrals of stationary Poisson point processes if mass-parameter goes to zero.
"The zero-mass limit problem for a relativistic spinless particle in an electromagnetic field." Proc. Japan Acad. Ser. A Math. Sci. 90 (3) 60 - 65, March 2014. https://doi.org/10.3792/pjaa.90.60