Domain wall delocalization, dynamics and fluctuations in an exclusion process with two internal states

We investigate the delocalization transition appearing in an
exclusion process with two internal states resp. on two parallel
lanes. At the transition, delocalized domain walls form in the
density profiles of both internal states, in agreement with a
mean-field approach. Remarkably, the topology of the system's phase
diagram allows for the delocalization of a (localized) domain wall
when approaching the transition. We quantify the domain wall's
delocalization close to the transition by analytic results obtained
within the framework of the domain wall picture. Power-law
dependences of the domain wall width on the distance to the
delocalization transition as well as on the system size are
uncovered, they agree with numerical results