Improving Our Knowledge on the <sup>229m</sup>Thorium Isomer: Toward a Test Bench for Time Variations of Fundamental Constants

Thirolf, P. G.; Wense, Lars von der

doi:10.1002/andp.201800381

Cited by 27 publications

(22 citation statements)

References 96 publications

(166 reference statements)

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“…In the following, several applications will be considered in more detail. A thorough discussion of potential applications for a nuclear clock was provided in [349].…”

Section: Potential Applicationsmentioning

confidence: 99%

The $$^{229}$$Th isomer: prospects for a nuclear optical clock

Wense

2020

Eur. Phys. J. A

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The proposal for the development of a nuclear optical clock has triggered a multitude of experimental and theoretical studies. In particular the prediction of an unprecedented systematic frequency uncertainty of about $$10^{-19}$$ 10 - 19 has rendered a nuclear clock an interesting tool for many applications, potentially even for a re-definition of the second. The focus of the corresponding research is a nuclear transition of the $$^{229}$$ 229 Th nucleus, which possesses a uniquely low nuclear excitation energy of only $$8.12\pm 0.11$$ 8.12 ± 0.11 eV ($$152.7\pm 2.1$$ 152.7 ± 2.1 nm). This energy is sufficiently low to allow for nuclear laser spectroscopy, an inherent requirement for a nuclear clock. Recently, some significant progress toward the development of a nuclear frequency standard has been made and by today there is no doubt that a nuclear clock will become reality, most likely not even in the too far future. Here we present a comprehensive review of the current status of nuclear clock development with the objective of providing a rather complete list of literature related to the topic, which could serve as a reference for future investigations.

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“…In the following, several applications will be considered in more detail. A thorough discussion of potential applications for a nuclear clock was provided in [349].…”

Section: Potential Applicationsmentioning

confidence: 99%

The $$^{229}$$Th isomer: prospects for a nuclear optical clock

Wense

2020

Eur. Phys. J. A

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“…(9) andĤ 0 I as well asĤ 0 † I were used as defined in Eq. (12). Next the Lindblad superoperator L[ρ] is considered, which is the second term on the right-hand side of Eq.…”

Section: The Optical Bloch Equations For a Two-level Systemmentioning

confidence: 99%

“…Further, it will advance the field of experimental nuclear quantum optics [7][8][9]. With an expected accuracy of 1.5 • 10 −19 [3] a nuclear optical clock may even surpass the best optical atomic clocks operational today [10,11], having the potential for utilization in, e.g., satellite-based navigation [12], relativistic geodesy [13], probing for timevariations of fundamental constants [14] and the search for topological dark matter [15]. Two different concepts of nuclear laser excitation have to be distinguished: direct excitation and excitation via the inverse electronic bridge (IEB) mechanism.…”

Section: Introductionmentioning

confidence: 99%

The theory of direct laser excitation of nuclear transitions

et al. 2020

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A comprehensive theoretical study of direct laser excitation of a nuclear state based on the density matrix formalism is presented. The nuclear clock isomer 229m Th is discussed in detail, as it could allow for direct laser excitation using existing technology and provides the motivation for this work. The optical Bloch equations are derived for the simplest case of a pure nuclear two-level system and for the more complex cases taking into account the presence of magnetic sub-states, hyperfine-structure and Zeeman splitting in external fields. Nuclear level splitting for free atoms and ions as well as for nuclei in a solid-state environment is discussed individually. Based on the obtained equations, nuclear population transfer in the low-saturation limit is reviewed. Further, nuclear Rabi oscillations, power broadening and nuclear twophoton excitation are considered. Finally, the theory is applied to the special cases of 229m Th and 235m U, being the nuclear excited states of lowest known excitation energies. The paper aims to be a didactic review with many calculations given explicitly.

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“…The 229 Th 3+ system is also attractive from several technical perspectives [33], design and simulation work has shown that a trapped Th 3+ ion could be developed in a compact and relatively low-cost package, making field deployment in a dispersed network achievable. In addition, the 229 Th nucleus is expected to be an excellent system for the search for time variation of fundamental constants [34][35][36]. To this date, a few groups worldwide have demonstrated thorium trapping in ion traps [37][38][39][40][41][42][43][44].…”

Section: Introductionmentioning

confidence: 99%

Studies of thorium and ytterbium ion trap loading from laser ablation for gravity monitoring with nuclear clocks

Piotrowski¹,

Scarabel²,

Lobino³

et al. 2020

OSA Continuum

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Compact and robust ion traps for thorium are enabling technology for the next generation of atomic clocks based on a low-energy isomeric transition in the thorium-229 nucleus. We aim at a laser ablation loading of single triply ionized thorium in a radio-frequency electromagnetic linear Paul trap. Detection of ions is based on a modified mass spectrometer and a channeltron with single-ion sensitivity. In this study, we successfully created and detected 232 Th + and 232 Th 2+ ions from plasma plumes, studied their yield evolution, and compared the loading to a quadrupole ion trap with Yb. We explore the feasibility of laser ablation loading for future low-cost 229 Th 3+ trapping. The thorium ablation yield shows a strong depletion, suggesting that we have ablated oxide layers from the surface and the ions were a result of the plasma plume evolution and collisions. Our results are in good agreement with similar experiments for other elements and their oxides.

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Improving Our Knowledge on the ^229mThorium Isomer: Toward a Test Bench for Time Variations of Fundamental Constants

Cited by 27 publications

References 96 publications

The $$^{229}$$Th isomer: prospects for a nuclear optical clock

The $$^{229}$$Th isomer: prospects for a nuclear optical clock

The theory of direct laser excitation of nuclear transitions

Studies of thorium and ytterbium ion trap loading from laser ablation for gravity monitoring with nuclear clocks

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Improving Our Knowledge on the 229mThorium Isomer: Toward a Test Bench for Time Variations of Fundamental Constants

Cited by 27 publications

References 96 publications

The $$^{229}$$Th isomer: prospects for a nuclear optical clock

The $$^{229}$$Th isomer: prospects for a nuclear optical clock

The theory of direct laser excitation of nuclear transitions

Studies of thorium and ytterbium ion trap loading from laser ablation for gravity monitoring with nuclear clocks

Contact Info

Product

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Improving Our Knowledge on the ^229mThorium Isomer: Toward a Test Bench for Time Variations of Fundamental Constants