Highly charged ions with<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>E</mml:mi></mml:math>1,<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>M</mml:mi></mml:math>1, and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>E</mml:mi></mml:math>2 transitions within laser range

Berengut, J. C.; Dzuba, V. A.; Flambaum, V. V.; Ong, Alex

doi:10.1103/physreva.86.022517

Cited by 73 publications

(58 citation statements)

References 44 publications

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“…In spite of the general trend of increasing energy intervals in HCIs, it is still possible to find clock transitions which are in optical range. This is due to electron energy level crossing while moving from the Modelung to the Coulomb level ordering with increasing of the ionization degree [11]. A number of optical clock transitions sensitive to variation of α were found and examined in Refs.…”

Section: Ionmentioning

confidence: 99%

“…(3) with F c replaced by J. The clock transition is sensitive to variation of the fine structure constant since it is a 4f to 5s transition [11]. It is convenient to present frequency dependence on α in the form ω(x) = ω 0 + qx, where x = α α 0 2 − 1 .…”

Section: Ionmentioning

confidence: 99%

“…A number of optical clock transitions sensitive to variation of α were found and examined in Refs. [10][11][12][13][14][15][16][17].…”

Section: Ionmentioning

confidence: 99%

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Optical clock sensitive to variations of the fine-structure constant based on theHo14+ion

2015

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We study the Ho 14+ ion as a candidate for extremely accurate and stable optical atomic clock which is sensitive to the time variation of the fine structure constant. We demonstrate that the proposed system has all desired features including relatively strong optical electric dipole and magnetic dipole transitions which can be used for cooling and detection. Zero quadrupole moments for the relevant states in the clock transition allows interrogating multiple ions to improve the clock stability.PACS numbers: 06.30. Ft, 06.20.Jr, 31.15.A, 32.30.Jc Theories unifying gravity with other fundamental interactions suggest a possibility for fundamental constants to vary in space or time (see, e.g. [1]). Searching for variation of the fundamental constants is an important way of testing these theories and finding new physics beyond standard model. Laboratory measurements limit the rate at which the fine structure constant α (α = e 2 /hc) varies in time to about 10 −17 per year [2,3]. On the other hand, the analysis of quasar absorption spectra shows that the fine structure constant may vary on astronomical scale along a certain direction in space forming the so called alpha-dipole [4]. Earth movement in the framework of the alpha-dipole (towards area of bigger alpha) 4f 6 5s 4f 5 s 2~4 0000 cm -1clock hfs-E1 λ~400 nm 6 H 5/2 (5) IonGround state Clock state Energy (cm −1 ) Er 14+ 4f 7 5s J = 4 4f 6 5s 2 J = 0 18555 Dy 10+ 4f 7 5p J = 3 4f 6 5p 2 J = 0 20835 Ho 14+ 4f 6 5s J = 0.5 4f 5 5s 2 J = 2.5 23800 would lead to the local time variation of α on the scale of 10 −19 per year [5]. To test the alpha-dipole hypothesis in terrestrial studies one needs a better accuracy in the laboratory measurements. The current best limit on the local time variation of α has been obtained by comparing Al + and Hg + optical clocks [2]. The result of this comparison limits time variation of alpha to (∂α/∂t)/α = (−1.6±2.3)×10 −17 yr −1 [2]), i.e. about two orders of magnitude improvement in accuracy is needed to test the alpha-dipole hypothesis. Current-best optical-clocks approach fractional uncertainty of ∼ 10 −18 [6][7][8]. However, the transitions used in these clocks are not sufficiently sensitive to the variation of α [9]. If α does change in time, the relative change δω/ω of the clock frequencies in any given period of time would be about an order of magnitude smaller than relative change in δα/α.It has been suggested in [10] to use highly-charged ions (HCI) as extremely accurate atomic clocks to probe possible variation of α. While HCIs are less sensitive to external perturbations due to their compact size, their sensitivity to variation of α is enhanced due to larger relativistic effects. In spite of the general trend of increasing energy intervals in HCIs, it is still possible to find clock transitions which are in optical range. This is due to electron energy level crossing while moving from the Modelung to the Coulomb level ordering with increasing

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Section: Ionmentioning

confidence: 99%

Section: Ionmentioning

confidence: 99%

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Optical clock sensitive to variations of the fine-structure constant based on theHo14+ion

2015

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“…Since state ordering in neutral atoms and hydrogen-like ions is different, there are must be change in ordering of s and f or p and f states at some intermediate ionization degree. In the vicitity of level crossing the frequencies of corresponding transitions are likely to be in optical region [19]. A number of optical transitions in HCI sensitive to variation of the fine structure constant were considered in Ref.…”

Section: Search For Variation Of the Fine Structure Constantmentioning

confidence: 99%

Highly charged ions for atomic clocks and search for variation of the fine structure constant

Dzuba¹,

Flambaum²

2015

TCP 2014

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We review a number of highly charged ions which have optical transitions suitable for building extremely accurate atomic clocks. This includes ions from Hf 12+ to U 34+ , which have the 4f 12 configuration of valence electrons, the Ir 17+ ion, which has a hole in almost filled 4f subshell, the Ho 14+ , Cf 15+ , Es 17+ and Es 16+ ions. Clock transitions in most of these ions are sensitive to variation of the fine structure constant, α (α = e 2 /hc). E.g., californium and einsteinium ions have largest known sensitivity to α-variation while holmium ion looks as the most suitable ion for experimental study. We study the spectra of the ions and their features relevant to the use as frequency standards. Currenf microwave cesium clock, which serves as definition of metric second, have Q ∼ 10 16 [7], best optical clocks approach Q ∼ 10 18 [8-10] mostly due to larger frequency. Further progress can be achieved by using optical transitions in HCI [1,2]. HCI are less sensitive to perturbations due to thier compact size. Therefore, quality factor Q = ω/δω can be larger than in neutral atoms due to smaller δω. In this paper we review some recent proposals for very accurate atomic clocks based on HCI and thier use for the search of time variation of the fine structure constant.

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“…The calculations are also needed to address the lack of experimental data, e.g. for such systems as superheavy elements [7,8] and highly-charged ions [9].…”

Section: Introductionmentioning

confidence: 99%

Combination of the single-double–coupled-cluster and the configuration-interaction methods: Application to barium, lutetium, and their ions

Dzuba

2014

Phys. Rev. A

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Highly charged ions withE1,M1, andE2 transitions within laser range

Cited by 73 publications

References 44 publications

Optical clock sensitive to variations of the fine-structure constant based on theHo14+ion

Optical clock sensitive to variations of the fine-structure constant based on theHo14+ion

Highly charged ions for atomic clocks and search for variation of the fine structure constant

Combination of the single-double–coupled-cluster and the configuration-interaction methods: Application to barium, lutetium, and their ions

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