Caesium atomic fountain clock is a primary frequency standard,which realizes the duration of second.Its performance is mostly dominated by the frequency accuracy,and the C-field induced second-order Zeeman frequency s...Caesium atomic fountain clock is a primary frequency standard,which realizes the duration of second.Its performance is mostly dominated by the frequency accuracy,and the C-field induced second-order Zeeman frequency shift is the major effect,which limits the accuracy improvement.By applying a high-precision current supply and high-performance magnetic shieldings,the C-field stability has been improved significantly.In order to achieve a uniform C-field,this paper proposes a doubly wound C-field solenoid,which compensates the radial magnetic field along the atomic flight region generated by the lead-out single wire and improves the accuracy evaluation of second-order Zeeman frequency shift.Based on the stable and uniform C-field,we launch the selected atoms to different heights and record the magnetically sensitive Ramsey transition|F=3,mF=-1→|F=4,mF=-1 central frequency,obtaining this frequency shift as 131.03×10^(-15)and constructing the C-field profile(σ=0.15 n T).Meanwhile,during normal operation,we lock NTSC-F2 to the central frequency of the magnetically sensitive Ramsey transition|F=3,mF=-1→|F=4,mF=-1 fringe for ten consecutive days and record this frequency fluctuation in time domain.The first evaluation of second-order Zeeman frequency shift uncertainty is 0.10×10^(-15).The total deviation of the frequency fluctuation on the clock transition induced by the C-field instability is less than 2.6×10^(-17).Compared with NTSC-F1,NTSC-F2,there appears a significant improvement.展开更多
Our recent article (Chin. Phys. Lett. 35 (2018)083201) measured the Zeeman shift of cesium atoms using an optical nanofiber. Before our work, Watkins et al.(Ref.[17] in our article) had demonstrated the Zeeman shift a...Our recent article (Chin. Phys. Lett. 35 (2018)083201) measured the Zeeman shift of cesium atoms using an optical nanofiber. Before our work, Watkins et al.(Ref.[17] in our article) had demonstrated the Zeeman shift also using an optical nanofiber in rubidium atoms. Watkins et al. reported on the observation展开更多
Based on the multiconfiguration Dirac-Hartree-Fock(MCDHF)method,similar models are employed to simultaneously calculate the first-order and second-order Zeeman coefficients as well as the hyperfine interaction constan...Based on the multiconfiguration Dirac-Hartree-Fock(MCDHF)method,similar models are employed to simultaneously calculate the first-order and second-order Zeeman coefficients as well as the hyperfine interaction constants of the related energy levels of ^(27)Al^(+)and its logical ions ^(9)Be^(+)and^(25)Mg^(+)in the^(27)Al^(+)optical clock.With less than 0.34%deviations from experimental values in Zeeman coefficients of^(27)Al^(+),these calculated parameters will be of great help for better evaluation of the systematic uncertainty.We also calculate the isotope shift parameters of the related energy levels,which could extend our knowledge and understanding of nuclear properties of these ions.展开更多
In the weak-magnetic-field approximation,we derived an expression of quadratic Zeeman shift coefficient of^(3)P_(0)^(o)clock state for^(88)Sr and^(87)Sr atoms.By using this formula and the multi-configuration Dirac-Ha...In the weak-magnetic-field approximation,we derived an expression of quadratic Zeeman shift coefficient of^(3)P_(0)^(o)clock state for^(88)Sr and^(87)Sr atoms.By using this formula and the multi-configuration Dirac-Hartree-Fock theory,the quadratic Zeeman shift coefficients were calculated.The calculated values C_(2)=-23.38(5)MHz/T^(2) for^(88)Sr and the^(3)p_(0)^(o),F=9/2,M_(F)=±9/2 clock states for^(87)Sr agree well with the other available theoretical and experimental values,especially the most accurate measurement recently.In addition,the calculated values of the^(3)p_(0)^(o),F=9/2,M_(F)=±9/2 clock states were also determined in our^(87)Sr optical lattice clock.The consistency with measurements verifies the validation of our calculation model.Our theory is also useful to evaluate the second-order Zeeman shift of the clock transition,for example,the new proposed^(1)S_(0),F=9/2,M_(F)=±5/2-^(3)P_(0)^(o),F=9/2,M_(F)=±3/2 transitions.展开更多
The study of magnetic field effects on the clock transition of Mg and Cd optical lattice clocks is scarce.In this work,the hyperfine-induced Landég-factors and quadratic Zeeman shift coefficients of the nsnp ^(3)...The study of magnetic field effects on the clock transition of Mg and Cd optical lattice clocks is scarce.In this work,the hyperfine-induced Landég-factors and quadratic Zeeman shift coefficients of the nsnp ^(3)P_(0)^(o) clock states for ^(111,113)Cd and ^(25)Mg were calculated by using the multi-configuration Dirac–Hartree–Fock theory.To obtain accurate values of these parameters,the impact of electron correlations and furthermore the Breit interaction and quantum electrodynamical effects on the Zeeman and hyperfine interaction matrix elements,and energy separations were investigated in detail.We also estimated the contributions from perturbing states to the Landég-factors and quadratic Zeeman shift coefficients concerned so as to truncate the summation over the perturbing states without loss of accuracy.Our calculations provide important data for estimating the first-and second-order Zeeman shifts of the clock transition for the Cd and Mg optical lattice clocks.展开更多
Nanofibers have many promising applications because of their advantages of high power density and ultralow saturated light intensity. We present here a Zeeman shift of the Doppler-broadened cesium D2 transition using ...Nanofibers have many promising applications because of their advantages of high power density and ultralow saturated light intensity. We present here a Zeeman shift of the Doppler-broadened cesium D2 transition using a tapered optical nanofiber in the presence of a magnetic field. When a weak magnetic field is parallel to the propagating light in the nanofiber, the Zeeman shift rates for different circularly polarized spectra are observed.For the ＋component, the typical linear Zeeman shift rates of = 3 and = 4 ground-state cesium atoms are measured to be 3.10（±0.19） MHz/G and 3.91（±0.16） MHz/G. For the -component, the values are measured to be-2.81（±0.25） MHz/G, and-0.78（±0.28） MHz/G. The Zeeman shift using the tapered nanofiber can help to develop magnetometers to measure the magnetic field at the narrow local region and the dispersive signal to lock laser frequency.展开更多
基金the National Key R&D Program of China(Grant No.2016YFF0200202)the Maintenance and Reformation Program for the Major Science and Technology Fundamental Devices of the Chinese Academy of Sciences(Grant No.DSS-WXGZ-2020-0005)the Foundation for Western Young Scholars,China(Grant No.XAB2018A06)。
文摘Caesium atomic fountain clock is a primary frequency standard,which realizes the duration of second.Its performance is mostly dominated by the frequency accuracy,and the C-field induced second-order Zeeman frequency shift is the major effect,which limits the accuracy improvement.By applying a high-precision current supply and high-performance magnetic shieldings,the C-field stability has been improved significantly.In order to achieve a uniform C-field,this paper proposes a doubly wound C-field solenoid,which compensates the radial magnetic field along the atomic flight region generated by the lead-out single wire and improves the accuracy evaluation of second-order Zeeman frequency shift.Based on the stable and uniform C-field,we launch the selected atoms to different heights and record the magnetically sensitive Ramsey transition|F=3,mF=-1→|F=4,mF=-1 central frequency,obtaining this frequency shift as 131.03×10^(-15)and constructing the C-field profile(σ=0.15 n T).Meanwhile,during normal operation,we lock NTSC-F2 to the central frequency of the magnetically sensitive Ramsey transition|F=3,mF=-1→|F=4,mF=-1 fringe for ten consecutive days and record this frequency fluctuation in time domain.The first evaluation of second-order Zeeman frequency shift uncertainty is 0.10×10^(-15).The total deviation of the frequency fluctuation on the clock transition induced by the C-field instability is less than 2.6×10^(-17).Compared with NTSC-F1,NTSC-F2,there appears a significant improvement.
文摘Our recent article (Chin. Phys. Lett. 35 (2018)083201) measured the Zeeman shift of cesium atoms using an optical nanofiber. Before our work, Watkins et al.(Ref.[17] in our article) had demonstrated the Zeeman shift also using an optical nanofiber in rubidium atoms. Watkins et al. reported on the observation
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11604385 and 91536106)the Natural Science Foundation of Hunan Province,China(Grant No.2019JJ50743)the Research Project of the National University of Defense Technology(Grant No.ZK17-03-11)。
文摘Based on the multiconfiguration Dirac-Hartree-Fock(MCDHF)method,similar models are employed to simultaneously calculate the first-order and second-order Zeeman coefficients as well as the hyperfine interaction constants of the related energy levels of ^(27)Al^(+)and its logical ions ^(9)Be^(+)and^(25)Mg^(+)in the^(27)Al^(+)optical clock.With less than 0.34%deviations from experimental values in Zeeman coefficients of^(27)Al^(+),these calculated parameters will be of great help for better evaluation of the systematic uncertainty.We also calculate the isotope shift parameters of the related energy levels,which could extend our knowledge and understanding of nuclear properties of these ions.
基金Project supported by the National Natural Science Foundation of China(Grant No.61775220)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB21030100)+1 种基金the Key Research Project of Frontier Science of the Chinese Academy of Sciences(Grant No.QYZDB-SSW-JSC004)the West Light Foundation of the Chinese Academy of Sciences(Grant No.XAB2018B17)。
文摘In the weak-magnetic-field approximation,we derived an expression of quadratic Zeeman shift coefficient of^(3)P_(0)^(o)clock state for^(88)Sr and^(87)Sr atoms.By using this formula and the multi-configuration Dirac-Hartree-Fock theory,the quadratic Zeeman shift coefficients were calculated.The calculated values C_(2)=-23.38(5)MHz/T^(2) for^(88)Sr and the^(3)p_(0)^(o),F=9/2,M_(F)=±9/2 clock states for^(87)Sr agree well with the other available theoretical and experimental values,especially the most accurate measurement recently.In addition,the calculated values of the^(3)p_(0)^(o),F=9/2,M_(F)=±9/2 clock states were also determined in our^(87)Sr optical lattice clock.The consistency with measurements verifies the validation of our calculation model.Our theory is also useful to evaluate the second-order Zeeman shift of the clock transition,for example,the new proposed^(1)S_(0),F=9/2,M_(F)=±5/2-^(3)P_(0)^(o),F=9/2,M_(F)=±3/2 transitions.
基金Project supported by the National Natural Science Foundation of China (Grant No.61775220)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDB21030100)the Key Research Project of Frontier Science of the Chinese Academy of Sciences (Grant No.QYZDB-SSW-JSC004)。
文摘The study of magnetic field effects on the clock transition of Mg and Cd optical lattice clocks is scarce.In this work,the hyperfine-induced Landég-factors and quadratic Zeeman shift coefficients of the nsnp ^(3)P_(0)^(o) clock states for ^(111,113)Cd and ^(25)Mg were calculated by using the multi-configuration Dirac–Hartree–Fock theory.To obtain accurate values of these parameters,the impact of electron correlations and furthermore the Breit interaction and quantum electrodynamical effects on the Zeeman and hyperfine interaction matrix elements,and energy separations were investigated in detail.We also estimated the contributions from perturbing states to the Landég-factors and quadratic Zeeman shift coefficients concerned so as to truncate the summation over the perturbing states without loss of accuracy.Our calculations provide important data for estimating the first-and second-order Zeeman shifts of the clock transition for the Cd and Mg optical lattice clocks.
基金Supported by National Key Research and Development Program of China under Grant No 2017YFA0304203the National Natural Science Foundation of China under Grant Nos 61675120 and 11434007+2 种基金the National Natural Science Foundation of China for Excellent Research Team under Grant No 61121064the Shanxi Scholarship Council of China,the 1331KSC,the PCSIRT under Grant No IRT13076the Applied Basic Research Project of Shanxi Province under Grant No 201601D202008
文摘Nanofibers have many promising applications because of their advantages of high power density and ultralow saturated light intensity. We present here a Zeeman shift of the Doppler-broadened cesium D2 transition using a tapered optical nanofiber in the presence of a magnetic field. When a weak magnetic field is parallel to the propagating light in the nanofiber, the Zeeman shift rates for different circularly polarized spectra are observed.For the ＋component, the typical linear Zeeman shift rates of = 3 and = 4 ground-state cesium atoms are measured to be 3.10（±0.19） MHz/G and 3.91（±0.16） MHz/G. For the -component, the values are measured to be-2.81（±0.25） MHz/G, and-0.78（±0.28） MHz/G. The Zeeman shift using the tapered nanofiber can help to develop magnetometers to measure the magnetic field at the narrow local region and the dispersive signal to lock laser frequency.
