2026-08-06 東京大学
時間軸での分業から、空間的な分業へ
＜関連情報＞
- https://www.t.u-tokyo.ac.jp/press/pr2026-08-06-003
- https://www.nature.com/articles/s41467-026-76017-1
空間的に定義されたラビ分光法による、途切れることのない光時計の計測 Spatially defined Rabi spectroscopy for uninterrupted optical clock interrogation
Koki Nishida,Ryoto Takeuchi,Shigenori Tsuji,Shoichi Okaba & Hidetoshi Katori
Nature Communications Published:06 August 2026
DOI:https://doi.org/10.1038/s41467-026-76017-1
Abstract
Optical lattice clocks achieve fractional frequency uncertainties of 10⁻¹⁸, yet stability is constrained by the dead time between cooling, preparation, interrogation, and detection. This sampling aliases local-oscillator noise into the clock signal (the Dick effect) and prevents continuous accumulation of oscillator phase information. We demonstrate spatially defined Rabi spectroscopy of ultracold ⁸⁸Sr atoms continuously transported in a moving optical lattice. A longitudinal excitation geometry preserves Lamb–Dicke confinement and suppresses Doppler broadening. Clock excitation is enabled only within a localised region by a transverse magnetic mixing field, defining the atom–laser interaction in space rather than in time and decoupling interrogation from preparation and detection. Transporting atoms at 16 mm s⁻¹ through a 12-mm interaction region yields a 1.2-Hz-wide spectrum close to the transit-time Fourier limit while maintaining uninterrupted atom delivery. This approach provides a practical route toward dead-time-free optical clock interrogation of continuously delivered atomic ensembles.
