Laser spectroscopic characterization of the nuclear clock isomer ${}^{229m}$Th

Abstract

The isotope ${}^{229}$Th is the only nucleus known to possess an excited state ${}^{229m}$Th in the energy range of a few electron volts, a transition energy typical for electrons in the valence shell of atoms, but about four orders of magnitude lower than common nuclear excitation energies. A number of applications of this unique nuclear system, which is accessible by optical methods, have been proposed. Most promising among them appears a highly precise nuclear clock that outperforms existing atomic timekeepers. Here we present the laser spectroscopic investigation of the hyperfine structure of ${}^{229m}$Th${}^{2+}$, yielding values of fundamental nuclear properties, namely the magnetic dipole and electric quadrupole moments as well as the nuclear charge radius. After the recent direct detection of this long-searched-for isomer, our results now provide detailed insight into its nuclear structure and present a method for its non-destructive optical detection.

18 pages

References in corpus (10)

• Direct detection of the 229Th nuclear clock transition
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Cited by in corpus (64)

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• Laser Spectroscopy for the Study of Exotic Nuclei
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• Roadmap towards the redefinition of the second
• Measurement of the ${}^{229}$Th isomer energy with a magnetic micro-calorimeter
• X-ray pumping of the Th-229 nuclear clock isomer
• Inner-shell clock transition in atomic thulium with small BBR shift
• Heavy-Ion Storage Rings and Their Use in Precision Experiments with Highly Charged Ions
• Sensitivity of ${}^{229}$Th nuclear clock transition to variation of the fine-structure constant
• Electronic bridge excitation in highly charged Th-229 ions
• Nuclear excitation of the ${}^{229}$Th isomer via defect states in doped crystals
• The ${}^{229}$Th isomer: prospects for a nuclear optical clock
• On an attempt to optically excite the nuclear isomer in Th-229
• ${}^{229}{\mathrm{ThF}}_4$ thin films for solid-state nuclear clocks
• Recent progress in laser spectroscopy of the actinides
• Theoretical predictions for the magnetic dipole moment of ${}^{229m}$Th
• Concepts for direct frequency-comb spectroscopy of ${}^{229\text{m}}$Th and an internal-conversion-based solid-state nuclear clock
• Nuclear charge radii of ${}^{229}$Th from isotope and isomer shifts
• The theory of direct laser excitation of nuclear transitions
• Trapping and sympathetic cooling of single thorium ions for spectroscopy
• ${}^{229m}$Th isomer from a nuclear model perspective
• Ground-state $g$ factor of highly charged ${}^{229}$Th ions: an access to the M1 transition probability between the isomeric and ground nuclear states
• An alternative approach to populate and study the ${}^{229}$Th nuclear clock isomer
• The electric quadrupole channel of the 7.8 eV ${}^{229}\mathrm{Th}$ transition
• Excitation of the ${}^{229}$Th nucleus via a two-photon electronic transition
• Hyperfine-structure-resolved laser spectroscopy of many-electron highly charged ions
• Resonant electronic-bridge excitation of the U-235 nuclear transition in ions with chaotic spectra
• Hyperfine interaction with the ${}^{229}$Th nucleus and its low lying isomeric state
• Effects of electrons on nuclear clock transition frequency in ${}^{229}$Th ions
• Driven electronic bridge processes via defect states in ${}^{229}$Th-doped crystals
• A scheme for excitation of thorium-229 nuclei based on the electronic bridge excitaion
• Nuclear coherent population transfer to the ${}^{229m}$Th isomer using x-ray pulses
• Trap-induced ac Zeeman shift of the thorium-229 nuclear clock frequency
• Nuclear Isomer Excitation in 229Th Atom by Super-Intense Laser Field
• Excitation and probing of low-energy nuclear states at high-energy storage rings
• Precision measurements with cold atoms and trapped ions
• Collective effects in ${}^{229}$Th-doped crystals
• Sympathetic cooling of trapped Th3+ alpha-recoil ions for laser spectroscopy
• The concept of laser-based conversion electron Mössbauer spectroscopy for a precise energy determination of ${}^{229m}$Th
• Alpha spectrometric characterization of thin ${}^{233}$U sources for ${}^{229\text{(m)}}$Th production
• On the sensitivity of nuclear clocks to new physics
• Towards an energy measurement of the internal conversion electron in the de-excitation of the Th-229 isomer
• Catching, trapping and in-situ-identification of thorium ions inside Coulomb crystals of ${}^{40}$Ca${}^{+}$ ions
• Absolute X-ray energy measurement using a high-accuracy angle encoder
• Internal conversion of the low energy ${}^{229m}$Th isomer in the Thorium anion
• Magnetic moments of short-lived nuclei with part-per-million accuracy: Towards novel applications of $\beta$-detected NMR in physics, chemistry and biology
• A proposed solution for the lifetime puzzle of the 229mTh+ isomer
• Development of a recoil ion source providing slow Th ions including ${}^{229(m)}$Th in a broad charge state distribution
• Free-space quasi-phase matching
• Studies of thorium and ytterbium ion trap loading from laser ablation for gravity monitoring with nuclear clocks
• Prediction of Nuclear Clock Transitions Frequency Difference between ${}^{229}$Th${}^{3+}$ and ${}^{229}$Th${}^{4+}$ via \textit{ab-initio} Self-Consistent Field Theory
• A continuous-wave vacuum ultraviolet laser for the nuclear clock
• Shift of nuclear clock transition frequency in ${}^{229}$Th ions due to hyperfine interaction
• Characterization of ${}^{233}$U alpha recoil sources for ${}^{229(m)}$Th beam production
• Relativistic atomic structure calculations in support of spectroscopy
• A cryogenic Paul trap for probing the nuclear isomeric excited state ${}^{229\text{m}}$Th${}^{3+}$
• Research progress of artificial intelligence empowered quantum communication and quantum sensing systems
• Production and chemical separation of ${}^{229}$Pa toward observation of $\gamma$ rays of ${}^{229\mathrm{m}}$Th
• Fluorescence calorimetry of an ion crystal
• Laser fluence-dependent production of molecular thorium ions in different charge states for trapped-ion experiments
• Comprehensive Assessment of ${\mathrm{Th}}^{3+}$ Properties for Nuclear Clock and Fundamental Physics Applications