Soutenance de thèse : Saverio Bocini

We study the non-equilibrium dynamics of quantum spin chains described by translationally-invariant Hamiltonians with short-range interactions. Special attention is given to initial states with localized inhomogeneities. Although such scenarios are often addressed by Generalized hydrodynamics (GHD), we consider special setups that go beyond this framework. First, we investigate the system at non-local scales that are not accounted for by GHD; by deriving exact results for connected correlations in partitioning protocols, the locality conditions necessary for GHD to work in the non-interacting case are established. Second, we explore macroscopic effects from local perturbations, showing that minimal modifications, such as a spin flip, of an otherwise-stationary initial state can induce a global reconfiguration of the spin chain; this phenomenon is observed perturbing jammed states and quantum scars. Finally, inspired by the low bipartite entanglement of the states exhibiting macroscopic effects from local perturbations, entanglement properties of the spectrum in non-interacting quantum spin chains are investigated; the study reveals that at most a finite small number of eigenstates satisfy the area law, also showing that several relevant models exhibit none.