Accurate control of magnetic fields is crucial for cold-atom experiments,often necessitating custom-designed control systems due to limitations in commercially available power supplies.Here,we demonstrate precise and ...Accurate control of magnetic fields is crucial for cold-atom experiments,often necessitating custom-designed control systems due to limitations in commercially available power supplies.Here,we demonstrate precise and flexible control of a static magnetic field by employing a field-programmable gate array and a feedback loop.This setup enables us to maintain exceptionally stable current with a fractional stability of 1 ppm within 30 s.The error signal of the feedback loop exhibited a noise level of 10^(-5)A·Hz^(-1/2)for control bandwidths below 10 k Hz.Utilizing this precise magnetic field control system,we investigate the second-order Zeeman shift in the context of cold-atom coherent population-trapping (CPT)clocks.Our analysis reveals the second-order Zeeman coefficient to be 574.21 Hz/G^(2),with an uncertainty of 1.36 Hz/G^(2).Consequently,the magnetic field stabilization system we developed allows us to achieve a second-order Zeeman shift below10^(-14),surpassing the long-term stability of current cold-atom CPT clocks.展开更多
基金supported by the National Key Research and Development Program of China (No. 2022YFA1404104)the National Natural Science Foundation of China (Nos. 12025509 and 12104521)。
文摘Accurate control of magnetic fields is crucial for cold-atom experiments,often necessitating custom-designed control systems due to limitations in commercially available power supplies.Here,we demonstrate precise and flexible control of a static magnetic field by employing a field-programmable gate array and a feedback loop.This setup enables us to maintain exceptionally stable current with a fractional stability of 1 ppm within 30 s.The error signal of the feedback loop exhibited a noise level of 10^(-5)A·Hz^(-1/2)for control bandwidths below 10 k Hz.Utilizing this precise magnetic field control system,we investigate the second-order Zeeman shift in the context of cold-atom coherent population-trapping (CPT)clocks.Our analysis reveals the second-order Zeeman coefficient to be 574.21 Hz/G^(2),with an uncertainty of 1.36 Hz/G^(2).Consequently,the magnetic field stabilization system we developed allows us to achieve a second-order Zeeman shift below10^(-14),surpassing the long-term stability of current cold-atom CPT clocks.
