Physical Review A
Precision measurement of the ground-state hyperfine constant for Be + 9 in a linear Paul trap via magnetically insensitive hyperfine transitions
Zhi-Yuan Ao, Wenli Bai, Qian-Yu Zhang, Wen-Cui Peng, Xin Tong
Abstract
Direct measurements of the ground-state magnetically insensitive hyperfine transition | F = 2 , m F = 0 〉 → | F = 1 , m F = 0 〉 of Be + 9 ions have been performed using microwave-driven state transfer. The Be + 9 ions are confined and laser cooled in a linear Paul trap, forming a Coulomb crystal. The transition frequencies have been measured over a magnetic-field range of ± 0.5 mT centered at zero magnetic field and the acquired data were fitted accounting for the high-order Zeeman effect. The hyperfine constant A is determined to be − 625.008 840 ( 35 ) MHz, achieving a relative precision of 5.6 × 10 − 8 .