Laser spectroscopy of triply charged 229Th isomer for a nuclear clock.
Laser spectroscopy of triply charged 229Th isomer for a nuclear clock.
复制标题
用于核钟的三电荷 229Th 异构体的激光光谱。
作者：
A. Yamaguchi;Y. Shigekawa;H. Haba;H. Kikunaga;Kenji Shirasaki;Michiharu Wada;H. Katori
Th-229(229)在基态(229gTh)和低位异构体(229mTh)之间具有光学核跃迁。基于这种核跃迁频率的核时钟由于对周围磁场1-5不敏感，有望超过现有原子钟。与其他带电状态相比，三重带电的第229 Th(229Th3+)最适合用于高精度的核时钟，因为它具有封闭的电子跃迁，能够进行激光冷却、激光诱导荧光检测和离子1、6-8的状态准备。尽管已经对处于核基态的229Th~(3+)进行了激光光谱研究8，但229mTh~(3+)的性质，包括其核衰变寿命，对于确定核钟跃迁的固有线宽至关重要，仍然未知。本文报道了用~(233)U源连续俘获~(229)mTh~(3+)，并用核态选择激光光谱测定了孤立~(229)mTh~(3+)的核衰变半衰期为1,400-300±600 S。此外，通过测定229mTh3+的超精细常数，我们将第229核钟对精细结构常数变化的灵敏度的不确定度降低了四倍。这些结果为229Th3+核钟及其在寻找新物理中的应用提供了关键参数。
Thorium-229 (229Th) possesses an optical nuclear transition between the ground state (229gTh) and low-lying isomer (229mTh). A nuclear clock based on this nuclear-transition frequency is expected to surpass existing atomic clocks owing to its insusceptibility to surrounding fields1-5. In contrast to other charge states, triply charged 229Th (229Th3+) is the most suitable for highly accurate nuclear clocks because it has closed electronic transitions that enable laser cooling, laser-induced fluorescence detection and state preparation of ions1,6-8. Although laser spectroscopic studies of 229Th3+ in the nuclear ground state have been performed8, properties of 229mTh3+, including its nuclear decay lifetime that is essential to specify the intrinsic linewidth of the nuclear-clock transition, remain unknown. Here we report the trapping of 229mTh3+ continuously supplied by a 233U source and the determination of nuclear decay half-life of the isolated 229mTh3+ to be 1,400 - 300 + 600 s through nuclear-state-selective laser spectroscopy. Furthermore, by determining the hyperfine constants of 229mTh3+, we reduced the uncertainty of the sensitivity of the 229Th nuclear clock to variations in the fine-structure constant by a factor of four. These results offer key parameters for the 229Th3+ nuclear clock and its applications in the search for new physics.
用空间量子传感器直接探测与太阳结合的超轻暗物质
影响因子：
14.1
作者：
Tsai, Yu-Dai;Eby, Joshua;Safronova, Marianna S.
通讯作者：
Safronova, Marianna S.
影响因子：
64.8
作者：
Seiferle, Benedict;von der Wense, Lars;Thirolf, Peter G.
通讯作者：
Thirolf, Peter G.