Trapping neutral fermions with kink-like potentials

Abstract

The intrinsically relativistic problem of neutral fermions subject to kink--like potentials ($\sim \mathrm{tanh} γx$) is investigated and the exact bound-state solutions are found. Apart from the lonely hump solutions for $E=\pm mc^{2}$, the problem is mapped into the exactly solvable Surm-Liouville problem with a modified Pöschl-Teller potential. An apparent paradox concerning the uncertainty principle is solved by resorting to the concepts of effective mass and effective Compton wavelength.