Observation of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi>S</mml:mi><mml:mn>0</mml:mn><mml:none /><mml:mprescripts /><mml:none /><mml:mn>1</mml:mn></mml:mmultiscripts><mml:mo>→</mml:mo><mml:mmultiscripts><mml:mi>P</mml:mi><mml:mn>0</mml:mn><mml:none /><mml:mprescripts /><mml:none /><mml:mn>3</mml:mn></mml:mmultiscripts></mml:math>Clock Transition in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:m

Rosenband, T.; Schmidt, Piet O.; Hume, David; Itano, Wayne M.; Fortier, Tara M.; Stalnaker, Jason; Kim, K.; Diddams, Scott A.; Koelemeij, J.C.J.; Bergquist, J. C.; Wineland, David J.

doi:10.1103/physrevlett.98.220801

Cited by 242 publications

(217 citation statements)

References 23 publications

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“…This quantum logic technique was first demonstrated, in principle, in 2005 on the 27 Al + 1 S 0 -3 P 1 transition with 9 Be + as the logic ion [54], and subsequently on the real 1 S 0 -3 P 0 clock transition in 2007 [55]. Recently, a second 27 Al + quantum logic clock was built with 25 Mg + as the logic ion, and comparisons between the two clocks have demonstrated a frequency uncertainty of approximately 9 × 10 −18 , with an instability of 2.8 × 10 −15 t −1/2 and a frequency difference between the clocks of −1.8 × 10 −17 [24].…”

Section: Single Trapped Ion Optical Clocksmentioning

confidence: 99%

When should we change the definition of the second?

Gill

2011

Phil. Trans. R. Soc. A.

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The microwave caesium (Cs) atomic clock has formed an enduring basis for the second in the International System of Units (SI) over the last few decades. The advent of laser cooling has underpinned the development of cold Cs fountain clocks, which now achieve frequency uncertainties of approximately 5 × 10 −16 . Since 2000, optical atomic clock research has quickened considerably, and now challenges Cs fountain clock performance. This has been suitably shown by recent results for the aluminium Al + quantum logic clock, where a fractional frequency inaccuracy below 10 −17 has been reported. A number of optical clock systems now achieve or exceed the performance of the Cs fountain primary standards used to realize the SI second, raising the issues of whether, how and when to redefine it. Optical clocks comprise frequency-stabilized lasers probing very weak absorptions either in a single cold ion confined in an electromagnetic trap or in an ensemble of cold atoms trapped within an optical lattice. In both cases, different species are under consideration as possible redefinition candidates. In this paper, I consider options for redefinition, contrast the performance of various trapped ion and optical lattice systems, and point to potential limiting environmental factors, such as magnetic, electric and light fields, collisions and gravity, together with the challenge of making remote comparisons of optical frequencies between standards laboratories worldwide.

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Section: Single Trapped Ion Optical Clocksmentioning

confidence: 99%

When should we change the definition of the second?

Gill

2011

Phil. Trans. R. Soc. A.

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“…3 is found to be consistent with the Heisenberg limit for the Al + clock [Eq. (11)], with a small offset due to the finite lifetime of the 3 P 0 state (τ = 20.6 s [41]). This indicates that the ratio stability is reaching the limit imposed by the atomic coherence of Al + .…”

Section: Measurements With Entangled States Of Atomsmentioning

confidence: 99%

Probing beyond the laser coherence time in optical clock comparisons

Hume

Leibrandt

2016

Phys. Rev. A

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We develop differential measurement protocols that circumvent the laser noise limit in the stability of optical clock comparisons by synchronous probing of two clocks using phase-locked local oscillators. This allows for probe times longer than the laser coherence time, avoids the Dick effect, and supports Heisenberg-limited measurement precision. We present protocols for such frequency comparisons and develop numerical simulations of the protocols with realistic noise sources. These methods provide a route to reduce frequency ratio measurement durations by more than an order of magnitude.

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“…This discrepancy is larger than the 5% experimental uncertainty and presently not understood. Somewhat smaller but still significant discrepancies exist between the above discussed trap measurements with In + [122] and Al + [123] and the corresponding state-of-theart calculations [130][131][132]. Clearly, more work needs to be done to reach a thorough understanding of the intricate hyperfine interaction between electron shell and atomic nucleus.…”

Section: Nuclear Effects On Atomic Half-livesmentioning

confidence: 99%

“…Such long lifetimes are attractive in view of obtaining ultraprecise optical frequency standards [120,121]. This has motivated experiments with trapped In + [122] and Al + [123] ions which provided experimental values for τ HFI (with uncertainties of ∼ 4% and ∼ 7%, respectively) from optical spectroscopy of the atomic-clock transitions 5s5p 3 P 0 → 5s 2 1 S 0 in 115 In + and 3s3p 3 P 0 → 3s 2 1 S 0 in 27 Al + . For Be-like 14 N 3+ τ HFI was inferred from a spectroscopic observation of a planetary nebula [124].…”

Section: Nuclear Effects On Atomic Half-livesmentioning

confidence: 99%

Storage ring at HIE-ISOLDE

Grieser

Litvinov

Raabe

et al. 2012

Eur. Phys. J. Spec. Top.

112

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We propose to install a storage ring at an ISOL-type radioactive beam facility for the first time. Specifically, we intend to install the heavy-ion, low-energy ring TSR at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored secondary beams that is unique in the world. The envisaged physics programme is rich and varied, spanning from investigations of nuclear groundstate properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. The TSR can also be used to remove isobaric contaminants from stored ion beams and for systematic studies within the neutrino beam programme. In addition to experiments performed using beams recirculating within the ring, cooled beams can also be extracted and exploited by external spectrometers for high-precision measurements. The existing TSR, which is presently in operation at the Max-Planck Institute for Nuclear Physics in Heidelberg, is well-suited and can be employed for this purpose. The physics cases, technical details of the existing ring facility and of the beam requirements at HIE-ISOLDE, together with the cost, time and manpower estimates for the transfer, installation and commissioning of the TSR at ISOLDE are discussed in the present technical design report.

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Observation of theS01→P03Clock Transition in

Cited by 242 publications

References 23 publications

When should we change the definition of the second?

When should we change the definition of the second?

Probing beyond the laser coherence time in optical clock comparisons

Storage ring at HIE-ISOLDE

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