Direct detection of the 229Th nuclear clock transition

Abstract

Today's most precise time and frequency measurements are performed with optical atomic clocks. However, it has been proposed that they could potentially be outperformed by a nuclear clock, which employs a nuclear transition instead of the atomic shell transitions used so far. By today there is only one nuclear state known which could serve for a nuclear clock using currently available technology, which is the isomeric first excited state in ${}^{229}$Th. Here we report the direct detection of this nuclear state, which is a further confirmation of the isomer's existence and lays the foundation for precise studies of the isomer's decay parameters. Based on this direct detection the isomeric energy is constrained to lie between 6.3 and 18.3 eV, and the half-life is found to be longer than 60 s for ${}^{229\mathrm{m}}$Th${}^{2+}$. More precise determinations appear in reach and will pave the way for the development of a nuclear frequency standard.

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• Prospects for a Nuclear Optical Frequency Standard based on Thorium-229
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• Results of a direct search using synchrotron radiation for the low-energy ${}^{229}$Th nuclear isomeric transition

Cited by in corpus (86)

• Search for New Physics with Atoms and Molecules
• Energy of the ${}^{229}$Th nuclear clock transition
• Frequency ratio of the ${}^{229\mathrm{m}}$Th nuclear isomeric transition and the ${}^{87}$Sr atomic clock
• Search for light scalar dark matter with atomic gravitational wave detectors
• Laser spectroscopic characterization of the nuclear clock isomer ${}^{229m}$Th
• Observation of the radiative decay of the ${}^{229}\mathrm{Th}$ nuclear clock isomer
• Measurement of the ${}^{229}$Th isomer energy with a magnetic micro-calorimeter
• Lifetime measurement of the ${}^{229}$Th nuclear isomer
• X-ray pumping of the Th-229 nuclear clock isomer
• Reduced transition probabilities for the gamma decay of the 7.8 eV isomer in ${}^{229}$Th
• Opportunities for Fundamental Physics Research with Radioactive Molecules
• A small weak scale from a small cosmological constant
• Energy of the ${}^{229}$Th Nuclear Clock Isomer Determined by Absolute $\gamma$-ray Energy Difference
• Atlas of Nuclear Isomers -- Second Edition
• Electronic bridge excitation in highly charged Th-229 ions
• A laser excitation scheme for ${}^{229\text{m}}$Th
• 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
• Femtosecond pumping of nuclear isomeric states by the Coulomb collision of ions with quivering electrons
• 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
• Cavity-QED determination of the natural linewidth of the ${}^{87}$Sr millihertz clock transition with 30$\mu$Hz resolution
• Nuclear charge radii of ${}^{229}$Th from isotope and isomer shifts
• The theory of direct laser excitation of nuclear transitions
• Excitation of ${}^{229m}$Th at Inelastic Scattering of Low Energy Electrons
• Trapping and sympathetic cooling of single thorium ions for spectroscopy
• ${}^{229m}$Th isomer from a nuclear model perspective
• Probing Multiple Electric Dipole Forbidden Optical Transitions in Highly Charged Nickel Ions
• XUV frequency comb operation in an astigmatism-compensated enhancement cavity
• Laser-induced electronic bridge for characterization of the ${}^{229\mathrm{m}}\mathrm{Th}\to {}^{229\mathrm{g}}\mathrm{Th}$ nuclear transition with a tunable optical laser
• Ground-state $g$ factor of highly charged ${}^{229}$Th ions: an access to the M1 transition probability between the isomeric and ground nuclear states
• High-Precision Ramsey-Comb Spectroscopy Based on High-Harmonic Generation
• The electric quadrupole channel of the 7.8 eV ${}^{229}\mathrm{Th}$ transition
• An alternative approach to populate and study the ${}^{229}$Th nuclear clock isomer
• Towards a 229Th-based nuclear clock
• Measuring the Th-229 nuclear isomer transition with U-233 doped crystals
• Excitation of the ${}^{229}$Th nucleus via a two-photon electronic transition
• Internal conversion from excited electronic states of ${}^{229}\mathrm{T}h$ ions
• Impact of the ionization of the atomic shell on the lifetime of the 229mTh isomer
• Impact of the ionization of the atomic shell on the lifetime of the ${}^{229m}$Th isomer
• Resonant electronic-bridge excitation of the U-235 nuclear transition in ions with chaotic spectra
• New Opportunities in Femto-to-Nanometer Scale with High-Intensity Lasers
• Laser Resonance Chromatography of Superheavy Elements
• 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
• Theoretical analysis of the electron bridge process in ${}^{229}$Th${}^{3+}$
• Nuclear coherent population transfer to the ${}^{229m}$Th isomer using x-ray pulses
• Nuclear Isomer Excitation in 229Th Atom by Super-Intense Laser Field
• Anomalous Hyperfine Structure of the ${}^{229}$Th Ground-State Doublet in Muonic Atom
• Magnetic hyperfine structure of the ground-state doublet in highly charged ions ${}^{229}$Th${}^{89+,87+}$ and the Bohr-Weisskopf effect
• Feasibility Study of Internal Conversion Electron Spectroscopy of ${}^{229m}$Th
• Nuclear resonant scattering experiment with fast time response: new scheme for observation of ${}^{229\mathrm{m}}$Th radiative decay
• ${}^{229}$Th Nuclear Spectroscopy in an Opaque Material: Laser-Based Conversion Electron Mössbauer Spectroscopy of ${}^{229}$ThO${}_2$
• Estimation of radiative half-life of ${}^{229m}$Th by half-life measurement of other nuclear excited states in ${}^{229}$Th
• Sympathetic cooling of trapped Th3+ alpha-recoil ions for laser spectroscopy
• Collective effects in ${}^{229}$Th-doped crystals
• Radiative Decay of the ${}^{229m}$Th Nuclear Clock Isomer in Different Host Materials
• Relativistic quantum clocks
• The concept of laser-based conversion electron Mössbauer spectroscopy for a precise energy determination of ${}^{229m}$Th
• Towards an energy measurement of the internal conversion electron in the de-excitation of the Th-229 isomer
• Alpha spectrometric characterization of thin ${}^{233}$U sources for ${}^{229\text{(m)}}$Th production
• Solid-State ${}^{229}\mathrm{Th}$ Nuclear Laser with Two-Photon Pumping
• Catching, trapping and in-situ-identification of thorium ions inside Coulomb crystals of ${}^{40}$Ca${}^{+}$ ions
• Development of a recoil ion source providing slow Th ions including ${}^{229(m)}$Th in a broad charge state distribution
• Internal conversion of the low energy ${}^{229m}$Th isomer in the Thorium anion
• Synthesis of cold and trappable fully stripped HCI's via antiproton-induced nuclear fragmentation in traps
• Nuclear excitation by two-photon electron transition
• Laser cooling and trapping of ${}^{224}$Ra${}^{+}$
• Cross section of the Coulomb excitation of ${}^{229m}$Th by low energy muons
• Magnetic resonance of rubidium atoms passing through a multi-layered transmission magnetic grating
• Lifetime of the singly charged ${}^{229}$Th nuclear isomer
• Energy response of X-rays under high flux conditions using a thin APD for the energy range of 6-33 keV
• Characterization of ${}^{233}$U alpha recoil sources for ${}^{229(m)}$Th beam production
• Shift of nuclear clock transition frequency in ${}^{229}$Th ions due to hyperfine interaction
• Measurement of photo- and radio-luminescence of thin ThF4 films
• A cryogenic Paul trap for probing the nuclear isomeric excited state ${}^{229\text{m}}$Th${}^{3+}$
• Proposal for a Nuclear Light Source
• Production and chemical separation of ${}^{229}$Pa toward observation of $\gamma$ rays of ${}^{229\mathrm{m}}$Th
• Highly efficient nuclear population transfer through physics-informed neural networks
• A new scheme for isomer pumping and depletion with high-power lasers
• 'Phase Transition' in the 'Thorium-Isomer Story'
• Fluorescence calorimetry of an ion crystal
• Theoretical evaluation of decay mode of ${}^{229m}\mathrm{Th}$ in solid samples