We report the effective slowing and trapping of Cs atoms in an ultrahigh-vacuum apparatus.The heated Cs atoms in an oven are slowed using a Zeeman slower after the oven chamber and then trapped using a magneto-optical...We report the effective slowing and trapping of Cs atoms in an ultrahigh-vacuum apparatus.The heated Cs atoms in an oven are slowed using a Zeeman slower after the oven chamber and then trapped using a magneto-optical trap in a science chamber.Compared to the traditional vacuum pressure of~10^(−7)Pa determined by the vapor pressure of Cs atoms in the oven chamber,the designed cold nipple and differential pumping tube are used between the oven and the oven chamber to achieve a lower vacuum pressure of~3.6×10^(−9)Pa.This is beneficial for achieving and maintaining an ultrahigh vacuum in the science chamber.We demonstrate the performance of our apparatus through the effective slowing of Cs atoms and an optimal magneto-optical trap.展开更多
A new iterative algorithm is proposed to reconstruct an unknown sparse signal from a set of projected measurements. Unlike existing greedy pursuit methods which only consider the atoms having the highest correlation w...A new iterative algorithm is proposed to reconstruct an unknown sparse signal from a set of projected measurements. Unlike existing greedy pursuit methods which only consider the atoms having the highest correlation with the residual signal, the proposed algorithm not only considers the higher correlation atoms but also reserves the lower correlation atoms with the residual signal. In the lower correlation atoms, only a few are correct which usually impact the reconstructive performance and decide the reconstruction dynamic range of greedy pursuit methods. The others are redundant. In order to avoid redundant atoms impacting the reconstructive accuracy, the Bayesian pursuit algorithm is used to eliminate them. Simulation results show that the proposed algorithm can improve the reconstructive dynamic range and the reconstructive accuracy. Furthermore, better noise immunity compared with the existing greedy pursuit methods can be obtained.展开更多
Enhancement factor K0, which characterizes NMR and EPR frequency shifts for Cs-129Xe, is measured for the first time. The enhancement factor r-o was measured to be （702±41） at 80 ℃ and （653±20） at 90 ℃...Enhancement factor K0, which characterizes NMR and EPR frequency shifts for Cs-129Xe, is measured for the first time. The enhancement factor r-o was measured to be （702±41） at 80 ℃ and （653±20） at 90 ℃, using the NMR frequency shift, detected by atomic magnetometer at a low magnetic field of 100 nT. This result is useful for predicting the EPR frequency shifts for Cs and the NMR frequency shifts for 129Xe in spin-exchange cells.展开更多
文摘We report the effective slowing and trapping of Cs atoms in an ultrahigh-vacuum apparatus.The heated Cs atoms in an oven are slowed using a Zeeman slower after the oven chamber and then trapped using a magneto-optical trap in a science chamber.Compared to the traditional vacuum pressure of~10^(−7)Pa determined by the vapor pressure of Cs atoms in the oven chamber,the designed cold nipple and differential pumping tube are used between the oven and the oven chamber to achieve a lower vacuum pressure of~3.6×10^(−9)Pa.This is beneficial for achieving and maintaining an ultrahigh vacuum in the science chamber.We demonstrate the performance of our apparatus through the effective slowing of Cs atoms and an optimal magneto-optical trap.
基金supported by the National Natural Science Foundation of China(50772107)National Key Basic Research Program of China(973)(2007CB210206)National High-Tech Research and Development Program of China(863)(2009AA05Z435)~~
基金supported by the National Natural Science Foundation of China (61172138)the Specialized Research Fund for the Doctoral Program of Higher Education (200807011007)the Natural Science Basic Research Program in Shannxi Province of China (2013JQ8040)
文摘A new iterative algorithm is proposed to reconstruct an unknown sparse signal from a set of projected measurements. Unlike existing greedy pursuit methods which only consider the atoms having the highest correlation with the residual signal, the proposed algorithm not only considers the higher correlation atoms but also reserves the lower correlation atoms with the residual signal. In the lower correlation atoms, only a few are correct which usually impact the reconstructive performance and decide the reconstruction dynamic range of greedy pursuit methods. The others are redundant. In order to avoid redundant atoms impacting the reconstructive accuracy, the Bayesian pursuit algorithm is used to eliminate them. Simulation results show that the proposed algorithm can improve the reconstructive dynamic range and the reconstructive accuracy. Furthermore, better noise immunity compared with the existing greedy pursuit methods can be obtained.
基金supported by the Key Program of the National Natural Science Foundation of China(Grant Nos.61227902,61273067,and 6137210)SAST Foundation of China
文摘Enhancement factor K0, which characterizes NMR and EPR frequency shifts for Cs-129Xe, is measured for the first time. The enhancement factor r-o was measured to be （702±41） at 80 ℃ and （653±20） at 90 ℃, using the NMR frequency shift, detected by atomic magnetometer at a low magnetic field of 100 nT. This result is useful for predicting the EPR frequency shifts for Cs and the NMR frequency shifts for 129Xe in spin-exchange cells.
