arXiv subjects

Tingyun Shi

Publications and source records attributed to Tingyun Shi.

6 recordsLinked to original sources

arXiv2025

A Liquid-Nitrogen-Cooled Ca+ Ion Optical Clock with a Systematic Uncertainty of 4.4E-19

We report a single-ion optical clock based on the 4S_1/2-3D_5/2 transition of the 40Ca+ ion, operated in a liquid nitrogen cryogenic environment,achieving a total systematic uncertainty of 4.4E-19. We employ a refined temperature evaluation scheme to reduce the frequency uncertainty due to blackbody radiation (BBR), and the 3D sideband cooling has been implemented to minimize the second-order Doppler shift. We have precisely determined the average Zeeman coefficient of the 40Ca+ clock transition to be 14.345(40) Hz/mT^2, thereby significantly reducing the quadratic Zeeman shift uncertainty. Moreover, the cryogenic environment enables the lowest reported heating rate due to ambient electric field noise in trapped-ion optical clocks.

physics.atom-ph↗

arXiv2023

Precision Measurement of M1 Optical Clock Transition in Ni12+

Highly charged ions (HCIs) have drawn significant interest in quantum metrology and in search for new physics. Among these, Ni12+ is considered as one of the most promising candidates for the next generation of HCI optical clocks, due to its two E1-forbidden transitions M1 and E2, which occur in the visible spectral range. In this work, we used the Shanghai-Wuhan Electron Beam Ion Trap to perform a high-precision measurement of the M1 transition wavelength. Our approach involved an improved calibration scheme for the spectra, utilizing auxiliary Ar+ lines for calibration and correction. Our final measured result of the M1 transition wavelength demonstrates a five-fold improvement in accuracy compared to our previous findings, reaching the sub-picometer level accuracy. In combination with our rigorous atomic-structure calculations to capture the electron correlations and relativistic effects, the quantum electrodynamic (QED) corrections were extracted. Moreover, comparing with an estimate of the one-electron QED contributions by using the GRASP2018 package, we found that the present experimental accuracy is high enough for testing the higher-order QED corrections for such a complex system with four electrons in the p subshell.

physics.atom-ph↗

arXiv2022

Measurement of infrared magic wavelength for an all-optical trapping of $^{40}$Ca$^{+}$ ion clock

For the first time, we experimentally determine the infrared magic wavelength for the $^{40}$Ca$^{+}$ $4s\, ^{2}\!S_{1/2} \rightarrow 3d\,^{2}\!D_{5/2}$ electric quadrupole transition by observation of the light shift canceling in $^{40}$Ca$^{+}$ optical clock. A "magic" magnetic field direction is chosen to make the magic wavelength insensitive to both the linear polarization purity and the polarization direction of the laser. The determined magic wavelength for this transition is 1056.37(9)~nm, which is not only in good agreement with theoretical predictions but also more precise by a factor of about 300. Using this measured magic wavelength we also derive the differential static polarizability to be $-44.32(32)$~a.u., which will be an important input for the evaluation of the blackbody radiation shift at room temperatures. Our work paves a way for all-optical-trapping of $^{40}$Ca$^{+}$ optical clock.

physics.atom-ph↗

arXiv2020

Role of hyperfine interaction in Landé $g$-factors of $^3\!P^o_0$ clock states

In the weak-magnetic-field approximation, we derived a general expression of hyperfine-induced Landé $g$-factors. By using this formula and the multi-configuration Dirac-Hartree-Fock theory, the $g$-factors were calculated for the $3s3p~^3\!P^o_0$ clock state in $^{27}$Al$^+$ and $5s5p~^3\!P^o_0$ in $^{87}$Sr. The present results, $δg^{(1)}_{\rm hfs}(^3\!P^o_0) = -1.183(6) \times 10^{-3}$ for $^{27}$Al$^+$ and $δg^{(1)}_{\rm hfs}(^3\!P^o_0) = 7.78(30) \times 10^{-5}$ for $^{87}$Sr agree with experimental values very well. Our theory is also useful to predict hyperfine-induced Landé $g$-factors for other atomic systems.

physics.atom-ph↗

arXiv2019

Universal Three-Body Parameter of Heavy-Heavy-Light systems with negative intraspecies scattering length

The Three-Body Parameter(3BP) $a^{\scriptscriptstyle(1)}_{\scriptscriptstyle-}$ is crucial to understanding Efimov physics, and a universal 3BP has been shown in experiments and theory in ultracold homonuclear gases. The 3BP of heteronuclear systems was predicted to possess much richer properties than the homonuclear counterparts for the large parameter space. In this work, we investigate the universal properties of $a^{\scriptscriptstyle(1)}_{\scriptscriptstyle-}$ for the Heavy-Heavy-Light(HHL) system with negative intraspecies scattering length $a_{\scriptscriptstyle HH}$. We find that $a^{\scriptscriptstyle(1)}_{\scriptscriptstyle-}$ follows a universal behavior determined by the van der Waals(vdW) interaction and the mass ratio. An analytic formula of $a^{\scriptscriptstyle(1)}_{\scriptscriptstyle-}$ is given as a function of $a_{\scriptscriptstyle HH}$, which allows an intuitive understanding of how does $a^{\scriptscriptstyle(1)}_{\scriptscriptstyle-}$ depend on the mass ratio and the vdW length $r_{\scriptscriptstyle vdW}$. In a special case, when the two heavy atoms are in resonance, $a^{\scriptscriptstyle(1)}_{\scriptscriptstyle-}$ is approximately a constant: $a^{\scriptscriptstyle(1)}_{\scriptscriptstyle-} = -(6.3\pm0.6)\, r_{\scriptscriptstyle vdW,HL}$.

cond-mat.quant-gas↗

arXiv2019

A low-energy compact Shanghai-Wuhan electron beam ion trap for extraction of highly charged ions

A low-energy, compact and superconducting electron beam ion trap (the Shanghai-Wuhan EBIT or SW-EBIT) for extraction of highly charged ions is presented. The magnetic field in the central drift tube of the SW-EBIT is approximately 0.21 T produced by a pair of high-temperature superconducting coils. The electron-beam energy of the SW-EBIT is in the range of 30-4000 eV, and the maximum electron-beam current is up to 9 mA. Acting as a source of highly charged ions, the ion-beam optics for extraction is integrated, including an ion extractor and an einzel lens. A Wien filter is then used to measure the charge-state distribution of the extracted ions. In this work, the tungsten ions below the charge state of 15 have been produced, extracted, and analyzed. The charge-state distributions and spectra in the range of 530-580 nm of tungsten ions have been measured simultaneously with the electron-beam energy of 279 eV and 300 eV, which preliminarily indicates that the 549.9 nm line comes from $W^{14+}$.

physics.atom-ph↗