  We study a one-dimensional classical stochastic kinetically constrained model
(KCM) inspired by Rydberg atoms in their "facilitated" regime, where sites can
flip only if a single of their nearest neighbours is excited. We call this
model "XOR-FA" to distinguish it from the standard Fredrickson-Andersen (FA)
model. We describe the dynamics of the XOR-FA model, including its relation to
simple exclusion processes in its domain wall representation. The interesting
relaxation dynamics of the XOR-FA is related to the prominence of large
dynamical fluctuations that lead to phase transitions between active and
inactive dynamical phases as in other KCMs. By means of numerical tensor
network methods we study in detail such transitions in the dynamical large
deviation regime.
