Microwave transitions between the neighboring levels that belong to the $^{1}$${\mathit{S}}_{0}$, $^{1}$${\mathit{P}}_{1}$, and $^{1}$${\mathit{D}}_{2}$ Rydberg series of ytterbium are studied for the principal quantum number ranging from 33 to 57. The term values and the quantum defects are determined by means of the general Rydberg-Ritz formula. The determined quantum defects show large linear energy dependence. The Zeeman effect measured for three $^{1}$${\mathit{P}}_{1}$ and one $^{1}$${\mathit{D}}_{2}$ Rydberg states under a weak external magnetic field is discussed.
Microwave transitions between the neighboring levels that belong to the ^{1}$${\mathit{S}}_{0}, ^{1}$${\mathit{P}}_{1}, and ^{1}$${\mathit{D}}_{2} Rydberg series of ytterbium are studied for the principal quantum number ranging from 33 to 57. The term values and the quantum defects are determined by means of the general Rydberg-Ritz formula. The determined quantum defects show large linear energy dependence. The Zeeman effect measured for three ^{1}$${\mathit{P}}_{1} and one ^{1}$${\mathit{D}}_{2} Rydberg states under a weak external magnetic field is discussed.
We present measurements of the hyperfine structure (HFS) of the nPJ Rydberg states for a large range of principal quantum number n(n=41−−55) employing microwave spectroscopy in an ultracold cesium Rydberg ensemble. A microwave field with $30\text{\ensuremath{-}}\textmu{}\mathrm{s}$ duration couples the $nS\ensuremath{\rightarrow}nP$ transition, yielding a narrow linewidth spectroscopy that approaches the Fourier limit, which allows us to resolve the hyperfine structure of nPJ states. By analyzing the hyperfine splittings of nPJ states, we determine the magnetic dipole HFS coupling constant AHFS,P1/2=3.760(26) GHz for the P1/2 state, and AHFS,P3/2=0.718(27) GHz and ${\overline{B}}_{\mathrm{HFS},{P}_{3/2}}=\ensuremath{-}0.084(102)$ GHz for the P3/2 state. Systematic uncertainties caused by stray electromagnetic field, microwave field power, and Rydberg interaction are analyzed. This measurement is significant for the investigation of Rydberg electrometry and quantum simulation with dipole interaction involving the nPJ state.
Rydberg atoms have a long history of scientific research, but they have recently seen a resurgence in popularity due to their advantages when dealing with coupled internal Rydberg states, or externally-coupled Rydberg atoms. The use of convenient RF and/or microwave generation techniques allows for straightforward coupling of many nearby Rydberg states, enabling quantum simulation studies, such as the generation of a synthetic lattice. Strontium is particularly attractive for Rydberg atom studies due to its optically active core, which allows for two-electron excited states and its conveniently accessible transition frequencies that match those available using commercial diode lasers. Before these experiments and applications can be realized however, precise knowledge of Rydberg state energies and quantum defects is required. Therefore, this work undertakes an extensive study of the quantum defects of both singly and doubly-excited strontium Rydberg atoms for a wide range of n and l. Precision microwave spectroscopy between nearby Rydberg states produces an improved self-consistent set of quantum defects for singly-excited 1S0, 1P1, 1D2, and 1F3 states, described by their corresponding Rydberg-Ritz parameters. Quantum defects and lifetimes for autoionizing two-electron-states are also presented. These elucidate the effects of core penetration by the “outer” excited Rydberg electron on transitions within the core ion and on the Rydberg level itself.
Abstract We present an experimental study of the Rydberg 1 S 0 - and 1 P 1 - series of ytterbium for principal quantum numbers in the range of n = 70–90. The study is performed using trap loss spectroscopy in a magneto-optical trap operating on the 6 1 S 0 → 6 1 P 1 transition at 399 nm. Compared to the commonly used Rydberg spectroscopy method using field-ionization and ion detection, trap loss spectroscopy is significantly simpler and requires a less sophisticated experimental setup. Using this method we determine relative values of the scalar and tensor electric polarizabilities of both, 6 s n s 1 S 0 - and 6 s n p 1 P 1 - Rydberg states.
We present precise measurements of the quantum defects of cesium nFJ Rydberg levels. We employ high-precision microwave spectroscopy of $(n+2){D}_{5/2}\ensuremath{\rightarrow}n{F}_{5/2,7/2}$ transitions for n=45 to 50 in a cold-atom setup. Cold cesium (n+2)D5/2 atoms, prepared via two-photon laser excitation, are probed by scanning weak microwave fields interacting with the atoms across the nF5/2,7/2 resonances. Transition spectra are acquired using state-selective electric-field ionization and time-gated ion detection. Transition-frequency intervals are obtained by Lorentzian fits to the measured spectral lines, which have linewidths ranging between 70 and 190 kHz, corresponding to about one to three times the Fourier limit. A comprehensive analysis of relevant line-shift uncertainties and line-broadening effects is conducted. We find quantum defect parameters ${\ensuremath{\delta}}_{0}({F}_{5/2})=0.033\phantom{\rule{0.16em}{0ex}}415\phantom{\rule{0.16em}{0ex}}37(70)$ and ${\ensuremath{\delta}}_{2}({F}_{5/2})=\ensuremath{-}0.2014(16)$, as well as ${\ensuremath{\delta}}_{0}({F}_{7/2})=0.033\phantom{\rule{0.16em}{0ex}}564\phantom{\rule{0.16em}{0ex}}6(13)$ and ${\ensuremath{\delta}}_{2}({F}_{7/2})=\ensuremath{-}0.2052(29)$, for J=5/2 and 7/2, respectively. Fine-structure parameters AFS and BFS for Cs nFJ are also obtained. Results are discussed in context with previous works, and the significance of the results is discussed.
Abstract In this work, we present a comprehensive experimental investigation of the isotope dependence of the binding energies of S - and D -Rydberg states in ytterbium. Using two-photon excitation via the intermediate 6 s 6 p 1 P 1 state in a magneto-optical trap, we measured excitation energies for the bosonic isotopes 172 Yb, 174 Yb, and 176 Yb, as well as for the fermionic isotopes 171 Yb ( I = 1 / 2 ) and 173 Yb ( I = 5 / 2 ), covering principal quantum numbers in the range 35 ⩽ n ⩽ 80 . For the bosonic isotopes, the isotope shifts are found to be independent of n , consistent with a single-channel quantum defect model. For 171 Yb, our results confirm previous high-precision measurements and multi-channel quantum defect modeling reported by Peper et al (2025), while for 173 Yb we provide the first detailed Rydberg spectra, revealing a complex level structure consistent with strong hyperfine-induced channel mixing and clear
The complex Rydberg structure of ytterbium atoms is shaped by multiple low-lying ion-core-excited states and strong channel interactions, which presents both opportunities and challenges for quantum information processing and precision metrology. In this work, we extend high-resolution microwave spectroscopy and multichannel quantum defect theory (MQDT) modeling of singly excited $6sn\ensuremath{\ell}$ Rydberg states in 174Yb and 171Yb to include the $\ensuremath{\ell}=3$ (f) and $\ensuremath{\ell}=4$ (g) series. Our measurements reveal $p\text{\ensuremath{-}}f$ mixing in odd-parity Rydberg states of 171Yb, which we incorporate by combined MQDT models for 6snp and 6snf series. Additionally, we observe that for $\ensuremath{\ell}=4$ the spin-orbit interaction dominates over the exchange interaction, such that the 6sng states are more accurately described in a jj-coupled basis. We validate our models by comparing the predicted Land\'e g factors and static dipole polarizabilities with experimental measurements, finding excellent agreement. These results provide important input for designing high-fidelity entangling gates with ytterbium atoms.