S. Uetake

Simultaneous magneto-optical trapping of lithium and ytterbium atoms towards production of ultracold polar molecules

We have successfully implemented the first simultaneous magneto-optical trapping (MOT) of lithium (6Li) and ytterbium (174Yb) atoms towards production of ultracold polar molecules of LiYb. For this purpose, we developed the dual atomic oven which contains both atomic species as an atom source and successfully observed the spectra of the Li and Yb atoms in the atomic beams from the dual atomic oven. We constructed the vacuum chamber including the glass cell with the windows made of zinc selenium (ZnSe) for the CO2 lasers, which are the useful light sources of optical trapping for evaporative and sympathetic cooling. Typical atom numbers and temperatures in the compressed MOT are 7×103 atoms, 640xa0μK for 6Li, 7×104 atoms, and 60xa0μK for 174Yb, respectively.

A scalable quantum computer with ultranarrow optical transition of ultracold neutral atoms in an optical lattice

We propose a new quantum-computing scheme using ultracold neutral ytterbium atoms in an optical lattice, especially in a monolayer of three-dimensional optical lattice. The nuclear Zeeman sublevels define a qubit. This choice avoids the natural phase evolution due to the magnetic dipole interaction between qubits. The Zeeman sublevels with large magnetic moments in the long-lived metastable state are also exploited to address individual atoms and to construct a controlled-multiqubit gate. Estimated parameters required for this scheme show that this proposal is scalable and experimentally feasible.

Inelastic Collisions in Optically Trapped Ultracold Metastable Ytterbium

We report measurement of inelastic loss in dense and cold metastable ytterbium (Yb[3P2]). Use of an optical far-off-resonance trap enables us to trap atoms in all magnetic sublevels, removing m-changing collisional trap loss from the system. Trapped samples of Yb[3P2] are produced at a density of 2 x 10(13) cm(-3) and temperature of 2 microK. We observe rapid two-body trap loss of Yb[3P2] and measure the inelastic collision rate constant 1.0(3) x 10(-11) cm3 s(-1). The existence of the fine-structure changing collisions between atoms in the 3P2 state is strongly suggested.

High-resolution laser spectroscopy of a Bose–Einstein condensate using the ultranarrow magnetic quadrupole transition

High-resolution laser spectroscopy of a Bose–Einstein condensate (BEC) was performed by using the ultranarrow magnetic quadrupole (6s2)1S0↔(6s6p)3P2 transition of ytterbium (Yb). The transition from the Doppler-broadened spectrum of thermal atoms to the asymmetric spectrum, reflecting the inhomogeneous density distribution of a BEC in a harmonic trap, was observed. The role of the inter-atomic interaction was highlighted by performing spectroscopy of a BEC loaded in a one-dimensional (1D) optical lattice.

High-Resolution Laser Spectroscopy of Ultracold Ytterbium Atoms

We have ail-optically created various quantum degenerate gases of ytterbium (Yb) atoms. The laser spectroscopy of ultra-narrow intercombination transitions ¹S₀-³P₀ and ¹S₀-³P₂ has been performed to probe the quantum degenerate gases of Yb atoms.