title: Quantum non-Markovianity induced by Anderson localization.
abstract: As discovered by P. W. Anderson, excitations do not propagate freely in a disordered lattice, but, due to destructive interference, they localise. As a consequence, when an atom interacts with a disordered lattice, one indeed observes a non-trivial excitation exchange between atom and lattice. Such non-trivial atomic dynamics will in general be characterised also by a non-trivial quantum information backflow, a clear signature of non-Markovian dynamics. To investigate the above scenario, we consider a quantum emitter, or atom, weakly coupled to a uniform coupled-cavity array (CCA). If initially excited, in the absence of disorder, the emitter undergoes a Markovian spontaneous emission by releasing all its excitation into the CCA (initially in its vacuum state). By introducing static disorder in the CCA the field normal modes become Anderson-localized, giving rise to a non-Markovian atomic dynamics. We show the existence of a functional relationship between a rigorous measure of quantum non-Markovianity and the CCA localization. We furthermore show that the average non-Markovianity of the atomic dynamics is well-described by a phenomenological model in which the atom is coupled, at the same time, to a single mode and to a standard - Markovian - dissipative bath.
authors.affiliation: Quantum Technology Lab, Dipartimento di Fisica, Università degli Studi di Milano, 20133 Milano, Italy.|INFN, Sezione di Milano, I-20133 Milano, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Lorenzo
authors.affiliation: Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, via Archirafi 36, I-90123 Palermo, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Lombardo
authors.affiliation: Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, via Archirafi 36, I-90123 Palermo, Italy.|NEST, Istituto Nanoscienze-CNR, I-56126 Pisa, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Ciccarello
authors.affiliation: Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, via Archirafi 36, I-90123 Palermo, Italy.|NEST, Istituto Nanoscienze-CNR, I-56126 Pisa, Italy.
authors.forename: G Massimo
authors.initials: GM
authors.lastname: Palma