title: Generalized constraints on quantum amplification.
abstract: We derive quantum constraints on the minimal amount of noise added in linear amplification involving input or output signals whose component operators do not necessarily have c-number commutators, as is the case for fermion currents. This is a generalization of constraints derived for the amplification of bosonic fields whose components possess c-number commutators.
authors.affiliation: LKB, Ecole Normale Superieure, 75231 Paris, France.
authors.forename: U
authors.initials: U
authors.lastname: Gavish
authors.forename: B
authors.initials: B
authors.lastname: Yurke
authors.forename: Y
authors.initials: Y
authors.lastname: Imry