Continuum p-wave Majorana interface mode
= Continuum p-wave Majorana interface mode
{c}
For the long-wavelength <Bogoliubov--de Gennes Hamiltonian> $H=-\mu(x)\tau_z-i\hbar\Delta\tau_x\partial_x$, a sign change from $\mu>0$ in a one-dimensional p-wave superconductor to $\mu<0$ in the vacuum binds a zero mode of width $\xi=\hbar\Delta/|\mu|$. Neglecting the quadratic <kinetic term> is valid when $|\mu|\ll m\Delta^2$ up to an inessential numerical factor.