Quantum quenches and thermalization on scale-free graphs

We show that after a quantum quench of the parameter controlling the number of particles in a Fermi– Hubbard model on scale-free graphs, the distribution of energy modes follows a power-law dependent on the quenched parameter and the connectivity of the graph. This paper contributes to the literature of quantum quenches on lattices, in which, for many integrable lattice models the distribution of modes after a quench thermalizes to a generalized Gibbs ensemble; this paper provides another example of distribution which can arise after relaxation. We argue that the main role is played by the symmetry of the underlying lattice which, in the case we study, is scale free, and to the distortion in the density of modes.