Significantly Improving the Escape Time of a Single <sup>40</sup>Ca<sup>+</sup> Ion in a Linear Paul Trap by Fast Switching of the Endcap Voltage

Cold atom clocks have made remarkable progresses in the last two decades and played critical roles in precision measurements. Primary Cs fountain frequency standards have achieved a total uncertainty of a few parts in 1016, and the best optical clock has reached a type B uncertainty below 10−18. Besides applications in the metrology, navigation, etc., ultra-stable and ultra-accurate atomic clocks have also become powerful tools in the basic scientific investigations. In this paper, we focus on the recent developments in the high-performance cold atomic clocks which can be used as frequency standards to calibrate atomic time scales. The basic principles, performances, and limitations of fountain clocks and optical clocks based on signal trapped ion or neutral atoms are summarized. Their applications in metrology and other areas are briefly introduced.

Section: Ion Trapping and Coolingmentioning

confidence: 99%

Cold atom clocks and their applications in precision measurements*

Dai¹,

Zheng²,

Liu³

et al. 2021

“…From the simulation model, we can calculate the dipole trap force is on the order of 10 −18 -10 −17 N, which is a level larger than the residual force that is the prerequisite for the all-optical trapping of a single 40 Ca + . The segmented structure is beneficial to precisely control the position of a single ion or even a string of ions, [20][21][22][23] and the comparatively short length and wide pole distance are essential to align the dipole beam with the trap center for the Gaussian shape of the highpower laser, which is also helpful for increasing the numerical aperture of the imaging system. The whole trap is enclosed in a vacuum chamber with a background gas pressure of ∼ 5 × 10 −9 Pa.…”

Section: Ion Trap Systemmentioning

confidence: 99%

Setup of a dipole trap for all-optical trapping*

Wang¹,

Chen²,

Huang³

et al. 2021

Self Cite

Micromotion induced by the radio-frequency field contributes greatly to the systematic frequency shifts of optical frequency standards. Although different strategies for mitigating this effect have been proposed, trapping ions optically has the potential to provide a generic solution to the elimination of micromotion. This could be achieved by trapping a single ion in the dipole trap composed of a highpower laser field. Here, we present the setup of the dipole trap composed of a 532 nm laser at a power of 10 W aiming to optically trap a single 40Ca+ and we observe an AC-Stark shift of the fluorescence spectrum line of ∼22 MHz caused by the 532 nm dipole beam. The beam waist of the dipole laser is several microns, which would provide a dipole potential strong enough for all-optical trapping of a single 40Ca+ ion.

“…Cold and ultracold atomic quantum gases play important roles and have broad application prospects in modern physics. Researches related to cold atomic systems include Bose-Einstein condensate, [1][2][3][4] superfluid, [5][6][7] atomic clocks, [8][9][10] topology, [11] etc. Compared to cold and ultracold atoms, molecules have some unique and superior properties.…”

Section: Introductionmentioning

confidence: 99%

The influence of collision energy on magnetically tuned ⁶Li-⁶Li Feshbach resonance

Zhang¹,

Han²,

Cong³

et al. 2022

The effect of collision energy on the magnetically tuned 6Li-6Li Feshbach resonance (FR) is investigated theoretically by using the coupled-channel (CC) method for the collision energy ranging from 1 to 100 (μK · kB). At the collision energy of 1 μK · kB, the resonance positions calculated are 543.152 G (s wave), 185.109 G (p wave |m l | = 0) and 185.113 G (p wave |m l | = 1), respectively. The p-wave FR near 185 G exibits a doublet structure of 4 mG, associated with dipole-dipole interaction. With the increase of the collision energy, it is found that the splitting width remains the same (4 mG), and that the resonance positions of s and p waves are shifted to higher magnetic fields with the increase of collision energy. The variation of the other quantities include the resonance width and the amplitude of the total scattering section are also discussed in detail. The thermally averaged elastic rate coefficients at T = 10, 15, 20, 25 K are calculated and compared.