title: Spin squeezing of a cold atomic ensemble with the nuclear spin of one-half.
abstract: In order to establish an applicable system for advanced quantum information processing based on the interaction between light and atoms, we have demonstrated a quantum nondemolition measurement with a collective spin of cold ytterbium atoms (171Yb), and have observed 1.8(-1.5)+2.4 dB spin squeezing. Since 171Yb atoms have only a nuclear spin of one-half in the ground state, the system constitutes the simplest spin ensemble and is thus robust against decoherence. We used very short pulses with a width of 100 ns, and as a result the interaction time became much shorter than the decoherence time, which is important for multistep quantum information processing.
authors.affiliation: Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Takano
authors.forename: M
authors.initials: M
authors.lastname: Fuyama
authors.forename: R
authors.initials: R
authors.lastname: Namiki
authors.forename: Y
authors.initials: Y
authors.lastname: Takahashi