Ultrastable optical, XUV and soft-x-ray clock transitions in open-shell highly charged ions

Abstract

Highly charged ions (HCIs) are insensitive to external perturbations and are attractive for the development of ultrastable clocks. However, only a few HCI candidates are known to provide optical clock transitions. In this Letter, we show that, as a result of strong relativistic effects, there are more than 100 suitable optical HCI clock candidates in more than 70 elements. Their transitions are embedded in the fine-structure splitting of the $n{d}^4$, $n{d}^5$ and $n{d}^6$ ground-state configurations with $n=3,4,5$ being the principal quantum numbers. The corresponding high multipolarity transitions in these ions have lifetimes and quality factors many orders of magnitude longer and larger, respectively, than those in state-of-the-art clocks. Their polarizabilities are also orders of magnitude smaller, rendering them more stable against external electromagnetic fields. Furthermore, within the same electronic configurations, the clock transitions in heavy ions scale up to the XUV and soft-x-ray region, thus enable the development of clocks based on shorter wavelengths. The existence of multiple clock transitions in different charge states of a single element, as well as in a whole isoelectronic sequence, would significantly enrich the detection of fine-structure constant variations, the search for new physics and the test of nuclear theories via high-precision spectroscopy.

arXiv comment4 pages in main text, 4 figures

References in corpus (35)

• Search for New Physics with Atoms and Molecules
• An ${}^{27}$Al${}^{+}$ quantum-logic clock with systematic uncertainty below $10^{-18}$
• Single-Ion Atomic Clock with $3\times 10^{-18}$ Systematic Uncertainty
• 1.5 $\mu$m lasers with sub 10 mHz linewidth
• Highly charged ions: optical clocks and applications in fundamental physics
• Energy of the ${}^{229}$Th nuclear clock transition
• Improved limits for violations of local position invariance from atomic clock comparisons
• Enhanced laboratory sensitivity to variation of the fine-structure constant using highly-charged ions
• Probing new light force-mediators by isotope shift spectroscopy
• Frequency ratio of the ${}^{229\mathrm{m}}$Th nuclear isomeric transition and the ${}^{87}$Sr atomic clock
• Observation of the radiative decay of the ${}^{229}\mathrm{Th}$ nuclear clock isomer
• Improved limits on the coupling of ultralight bosonic dark matter to photons from optical atomic clock comparisons
• An Optical Atomic Clock Based on a Highly Charged Ion
• Highly-charged ions as a basis of optical atomic clockwork of exceptional accuracy
• Evidence for Nonlinear Isotope Shift in Yb${}^{+}$ Search for New Boson
• Hole transitions in multiply-charged ions for precision laser spectroscopy and searching for alpha-variation
• Highly-charged ions for atomic clocks, quantum information, and search for $\alpha$-variation
• Precision calculation of blackbody radiation shifts for optical frequency metrology
• Inner-shell clock transition in atomic thulium with small BBR shift
• Extreme Ultraviolet Radiation With Coherence Time Greater Than 1 s
• The Heidelberg compact electron beam ion traps
• Blackbody radiation shift assessment for a lutetium ion clock
• Sensitivity of ${}^{229}$Th nuclear clock transition to variation of the fine-structure constant
• Improved isotope-shift-based bounds on bosons beyond the Standard Model through measurements of the ${}^2$D${}_{3/2}{-}^2$D${}_{5/2}$ interval in Ca${}^{+}$
• Optical transitions in highly-charged californium ions with high sensitivity to variation of the fine-structure constant
• Magnetic-dipole transitions in highly-charged ions as a basis of ultra-precise optical clocks
• Stringent test of QED with hydrogenlike tin
• Generalized King linearity and new physics searches with isotope shifts
• Detection of the $5p-4f$ orbital crossing and its optical clock transition in Pr${}^{9+}$
• Broadband high-resolution x-ray frequency combs
• Optical clocks based on the Cf${}^{15+}$ and Cf${}^{17+}$ ions
• Measurements of ${}^{27}$Al${}^{+}$ and ${}^{25}$Mg${}^{+}$ magnetic constants for improved ion clock accuracy
• Hyperfine-structure-resolved laser spectroscopy of many-electron highly charged ions
• Quadruply Ionized Barium as a Candidate for a High-Accuracy Optical Clock
• Interrogating the temporal coherence of EUV frequency combs with highly charged ions

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