title: Quantum study of information delay in electromagnetically induced transparency.
abstract: Using electromagnetically induced transparency (EIT), it is possible to delay and store light in atomic ensembles. Theoretical modeling and recent experiments have suggested that the EIT storage mechanism can be used as a memory for quantum information. We present experiments that quantify the noise performance of an EIT system for conjugate amplitude and phase quadratures. It is shown that our EIT system adds excess noise to the delayed light that has not hitherto been predicted by published theoretical modeling. In analogy with other continuous-variable quantum information systems, the performance of our EIT system is characterized in terms of conditional variance and signal transfer.
authors.affiliation: ARC COE for Quantum-Atom Optics, Australian National University, Canberra, ACT 0200, Australia.
authors.forename: M T L
authors.initials: MT
authors.lastname: Hsu
authors.forename: G
authors.initials: G
authors.lastname: Hétet
authors.forename: O
authors.initials: O
authors.lastname: Glöckl
authors.forename: J J
authors.initials: JJ
authors.lastname: Longdell
authors.forename: B C
authors.initials: BC
authors.lastname: Buchler
authors.forename: H-A
authors.initials: HA
authors.lastname: Bachor
authors.forename: P K
authors.initials: PK
authors.lastname: Lam