title: Inverting quantum decoherence by classical feedback from the environment.
abstract: We show that for qubits and qutrits it is always possible to perfectly recover quantum coherence by performing a measurement only on the environment, whereas for dimension d >3 there are situations where recovery is impossible, even with complete access to the environment. For qubits, the minimal amount of classical information to be extracted from the environment equals the entropy exchange.
authors.affiliation: QUIT Group, Dipartimento di Fisica A. Volta, Università di Pavia, via A. Bassi 6, I-27100 Pavia, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Buscemi
authors.forename: Giulio
authors.initials: G
authors.lastname: Chiribella
authors.forename: Giacomo
authors.initials: G
authors.lastname: Mauro D'Ariano