title: Parametric amplification of vacuum fluctuations in a spinor condensate.
abstract: Parametric amplification of vacuum fluctuations is crucial in modern quantum optics, enabling the creation of squeezing and entanglement. We demonstrate the parametric amplification of vacuum fluctuations for matter waves using a spinor F=2 87Rb condensate. Interatomic interactions lead to correlated pair creation in the mF=±1 states from an initial mF=0 condensate, which acts as a vacuum for mF≠0. Although this pair creation from a pure mF=0 condensate is ideally triggered by vacuum fluctuations, unavoidable spurious initial mF=±1 atoms induce a classical seed which may become the dominant triggering mechanism. We show that pair creation is insensitive to a classical seed for sufficiently large magnetic fields, demonstrating the dominant role of vacuum fluctuations. The presented system thus provides a direct path towards the generation of nonclassical states of matter.
authors.affiliation: Institut für Quantenoptik, Leibniz Universität Hannover, D-30167 Hannover, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Klempt
authors.forename: O
authors.initials: O
authors.lastname: Topic
authors.forename: G
authors.initials: G
authors.lastname: Gebreyesus
authors.forename: M
authors.initials: M
authors.lastname: Scherer
authors.forename: T
authors.initials: T
authors.lastname: Henninger
authors.forename: P
authors.initials: P
authors.lastname: Hyllus
authors.forename: W
authors.initials: W
authors.lastname: Ertmer
authors.forename: L
authors.initials: L
authors.lastname: Santos
authors.forename: J J
authors.initials: JJ
authors.lastname: Arlt