Fermionic spectral walls in kink collisions

Abstract

We show that a spectral wall, i.e., an obstacle in the dynamics of a bosonic soliton, which arises due to the transition of a normal mode into the continuum spectrum, exists after coupling the original bosonic model to fermions. This spectral wall can be experienced if the boson or fermion field is in an excited state. Furthermore, while passing through a spectral wall, an incoming kink-fermion bound state can be separated into purely bosonic kink, which continues to move to spatial infinity and a fermionic cloud that spreads in the region before the wall.

(Anti-)Stokes scattering on kinks

“…This bulk dynamics is itself quite rich. There are spectral walls [12,13] beyond which internal excitations of kinks escape into the continuum. While these have striking consequences classically, in the quantum theory they are rather smooth [14].…”