Nuclear clocks based on resonant excitation of γ-transitions

Peik, E.; Okhapkin, M.

doi:10.1016/j.crhy.2015.02.007

Cited by 111 publications

(95 citation statements)

References 57 publications

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“…On the other hand, there might be novel concepts with prospects to achieve, e.g., a reduced interaction of the clock transition with all sorts of environmental perturbations. A transition between two isomeric states in 229 Th has attracted much consideration (see, e.g., [64] in this dossier) for such a possibly better-isolated clock transition. PTB has a project [65] to find this clock transition via bridge processes [66] in ion clouds and in crystals doped with 229 Th.…”

Section: Conclusion and Possible Roadmapmentioning

confidence: 99%

Towards a redefinition of the second based on optical atomic clocks

Riehle

2015

Comptes Rendus. Physique

142

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Future redefinition of the second Frequency and time dissemination Mots-clés :Horloges optiques atomiques Étalons de fréquence Redéfinition future de la seconde Diffusion des fréquences et des signaux horairesThe rapid increase in accuracy and stability of optical atomic clocks compared to the caesium atomic clock as the primary standard of time and frequency asks for a future redefinition of the second in the International System of Units (SI). The status of the optical clocks based on either single ions in radio-frequency traps or on neutral atoms stored in an optical lattice is described, with special emphasis on the current work at the Physikalisch-Technische Bundesanstalt (PTB, Braunschweig, Germany). Besides the development and operation of different optical clocks with estimated fractional uncertainties in the 10 −18 range, the supporting work on ultra-stable lasers as core elements and the means to compare remote optical clocks with transportable standards, optical fibres, or frequency ratios is reported. Finally, the conditions, methods and next steps are discussed, which are the prerequisites for a future redefinition of the second. © 2015 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.r é s u m é L'amélioration rapide en termes de précision et de stabilité des horloges atomiques optiques par rapport à l'horloge atomique au césium, qui constitue la référence primaire pour le temps et la fréquence, appelle une future redéfinition de la seconde dans le système international d'unités (SI). L'état d'avancement des horloges optiques basées sur des ions uniques dans des pièges radiofréquence ou sur des atomes neutres confinés dans le réseau optique est décrit, en insistant particulièrement sur le travail en cours à la PhysikalischTechnische Bundesanstalt (PTB, Brunswick, Allemagne). À côté du développement et de la mise en oeuvre de différentes horloges optiques avec des incertitudes fractionnelles estimées d'un ordre de grandeur de 10 −18 , les travaux sous-jacents sur les lasers ultra-stables comme éléments centraux ainsi que les moyens de comparer les horloges optiques lointaines avec des étalons transportables, des fibres optiques ou des rapports de fréquence * 507 sont exposés. Finalement, les conditions, les méthodes et les prochaines étapes sont discutées, qui sont des prérequis à une redéfinition de la seconde.

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Section: Conclusion and Possible Roadmapmentioning

confidence: 99%

Towards a redefinition of the second based on optical atomic clocks

Riehle

2015

Comptes Rendus. Physique

142

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“…Significant progress is expected in laboratory measurements in the coming years: with forthcoming molecular and nuclear clocks, particularly those based on Thorium229 [119], a sensitivity as high as 10 −21 yr −1 may be achieved. The Oklo natural nuclear reactor is another complementary probe of the stability of fundamental couplings.…”

Section: Other Probesmentioning

confidence: 99%

The status of varying constants: a review of the physics, searches and implications

2017

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Abstract. The observational evidence for the recent acceleration of the universe demonstrates that canonical theories of cosmology and particle physics are incomplete-if not incorrect-and that new physics is out there, waiting to be discovered. A key task for the next generation of laboratory and astrophysical facilities is to search for, identify and ultimately characterize this new physics. Here we highlight recent developments in tests of the stability of nature's fundamental couplings, which provide a direct handle on new physics: a detection of variations will be revolutionary, but even improved null results provide competitive constraints on a range of cosmological and particle physics paradigms. A joint analysis of all currently available data shows a preference for variations of α and µ at about the two-sigma level, but inconsistencies between different sub-sets (likely due to hidden systematics) suggest that these statistical preferences need to be taken with caution. On the other hand, these measurements strongly constrain Weak Equivalence Principle violations. Plans and forecasts for forthcoming studies with facilities such as ALMA, ESPRESSO and the ELT, which should clarify these issues, are also discussed, and synergies with other probes are briefly highlighted. The goal is to show how a new generation of precision consistency tests of the standard paradigm will soon become possible.PACS numbers: 98.80.Es, 95.36.+x, 98.62.Ra,

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“…This state is expected to provide access to a number of interesting physical effects, including the decay of the nuclear isomeric level via the electronic bridge mechanism in certain chemical environments [3][4][5], cooperative spontaneous emission [6] in a system of excited nuclei, the Mößbauer effect in the optical range [7], sensitive tests of the variation of the fine structure constant and the strong interaction parameter [8][9][10][11], a check of the exponentiality of the decay law of an isolated metastable state at long times [12], and accelerated α-decay of the 229 Th nuclei via the low energy isomeric state [13]. In addition, two applications that may have a significant technological impact were proposed: a new metrological standard for time [14] or the "nuclear clock" [15][16][17][18], and a nuclear laser (or gamma ray laser) in the optical range [7].…”

Section: Introductionmentioning

confidence: 99%

Radiative lifetime and energy of the low-energy isomeric level inTh229

et al. 2015

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We estimate the range of the radiative lifetime and energy of the anomalous, low-energy 3/2 + (7.8± 0.5 eV) state in the 229 Th nucleus. Our phenomenological calculations are based on the available experimental data for the intensities of M 1 and E2 transitions between excited levels of the 229 Th nucleus in the K π [N nZ Λ] = 5/2 + [633] and 3/2 + [631] rotational bands. We also discuss the influence of certain branching coefficients, which affect the currently accepted measured energy of the isomeric state. From this work, we establish a favored region where the transition lifetime and energy should lie at roughly the 90% confidence level. We also suggest new nuclear physics measurements, which would significantly reduce the ambiguity in the present data.

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Nuclear clocks based on resonant excitation of γ-transitions

Cited by 111 publications

References 57 publications

Towards a redefinition of the second based on optical atomic clocks

Towards a redefinition of the second based on optical atomic clocks

The status of varying constants: a review of the physics, searches and implications

Radiative lifetime and energy of the low-energy isomeric level inTh229

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