相关论文: Sub-ppb measurement of a fundamental band rovibrat…

We describe experimental investigations on an optical frequency standard based on a laser cooled 171Yb+ ion confined in a radiofrequency Paul trap. The electric-quadrupole transition from the 2S1/2(F=0) ground state to the 2D3/2(F=2) state…

The Lambda-doublet transitions in CH at 3.3 and 0.7 GHz are unusually sensitive to variations in the fine-structure constant and the electron-to-proton mass ratio. We describe methods used to measure the frequencies of these transitions…

Methane is a key spherical-top molecule, yet restrictive selection rules for one-photon transitions have prevented determination of its ground state (GS) energies with state-of-the-art kHz-level accuracy. We report the GS rotational energy…

We report the first direct measurement of the hyperfine transition of the ground state positronium. The hyperfine structure between ortho-positronium and para-positronium is about 203 GHz. We develop a new optical system to accumulate about…

We present a solid-state laser system that generates over 200 mW of continuous-wave, narrowband light, tunable from 316.3 nm - 317.7 nm and 318.0 nm - 319.3 nm. The laser is based on commercially available fiber amplifiers and optical…

We report on the observation and coherent excitation of atoms on the narrow inner-shell orbital transition, connecting the erbium ground state $[\mathrm{Xe}] 4f^{12} (^3\text{H}_6)6s^{2}$ to the excited state $[\mathrm{Xe}]…

The rovibrational transition frequencies of molecular hydrogen ions (MHI) can be accurately computed using ab initio nonrelativistic quantum electrodynamics. A subset of the fundamental constants are required input. We analyze how, once…

In this paper, we present the spectroscopy of 6P$_{1/2}$ state in $^{87}$Rb using double resonance technique at $780~\text{nm}$ and $421~\text{nm}$. The double resonance technique is implemented using electromagnetically induced…

The possible use of high-resolution rovibrational spectroscopy of the hydrogen molecular ions H + 2 and HD + for an independent determination of several fundamental constants is analyzed. While these molecules had been proposed for…

Quasi-forbidden electronic transitions in atoms and quasi-degenerate vibronic transitions in molecules serve as powerful probes of hypothetical temporal variations of fundamental constants. Computation of the sensitivity of a transition to…

We report the first absolute frequency measurements for the $5s5p^{3}$P$_{0}\to5s6d^{3}$D$_{1}$ transition at 394 nm for all the stable strontium isotopes by utilizing repumping induced spectroscopy in a magneto-optical trap. Absolute…

We have remeasured the absolute $1S$-$2S$ transition frequency $\nu_{\rm {H}}$ in atomic hydrogen. A comparison with the result of the previous measurement performed in 1999 sets a limit of $(-29\pm 57)$ Hz for the drift of $\nu_{\rm {H}}$…

Solid atomic hydrogen is one of the simplest systems to undergo a metal-insulator transition. Near the transition, the electronic degrees of freedom become strongly correlated and their description provides a difficult challenge for…

Frequency combs have revolutionized optical frequency metrology, allowing one to determine highly accurate transition frequencies of a wealth of molecular species. Despite a recognized scientific interest, these progresses have only…

We report the observation and analysis of spectra in part of the near-infrared spectrum of C$_2$H, originating in rotational levels in the ground and lowest two excited bending vibrational levels of the ground $\tilde{X}\,^2\Sigma^+$ state.…

We report a 4.9\,ppb measurement of the positronium $\text{1}^\text{3}\text{S}_\text{1} \to \text{2}^\text{3}\text{S}_\text{1}$ interval using continuous-wave two-photon laser spectroscopy. The transition is detected via photoionization by…

We report precision measurement of aluminum atoms ${^{2}P_{1/2}}-{^{2}S_{1/2}}$ transition at 394 nm and ${^{2}P_{3/2}}-{^{2}S_{1/2}}$ transition at 396 nm in a hollow-cathode lamp (HCL). Both absorption spectroscopy and saturated…

A new $^{11}$Be($d,p$)$^{12}$Be transfer reaction experiment was carried out in inverse kinematics at 26.9$A$ MeV, with special efforts devoted to the determination of the deuteron target thickness and of the required optical potentials…

Precision isotope shift metrology in the deep-UV region has been performed for all bosonic isotopes of mercury with a zero nuclear spin, by using the technique of frequency-comb referenced, wavelength-modulated, saturated absorption…

Accepted values of the masses of several subatomic particles have been under debate since recent measurements in Penning traps produced more precise yet incompatible results, implying possible inconsistencies in closely related physical…