Precision Microwave Measurement of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mn>2</mml:mn><mml:mrow><mml:msup><mml:mrow><mml:mi /></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="italic">P</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mi>−</mml:mi><mml:mn>2</mml:mn><mml:mrow><mml:msup><mml:mrow><mml:mi /></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></

Storry, C. H.; George, M. C.; Hessels, E. A.

doi:10.1103/physrevlett.84.3274

Cited by 58 publications

(53 citation statements)

References 17 publications

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“…The readily accessible 2 3 P and 3 3 P manifolds have been the focus of much experimental activity, particularly following the introduction of optical frequency combs (see Maddaloni et al (2009) Among all triplet level transitions, that between the 2 3 S and 2 3 P states in 4 He at 1083 nm is by far the most experimentally studied. In a series of experiments (Borbely et al, 2009;Castillega et al, 2000;Frieze et al, 1981;Giusfredi et al, 2005;Minardi et al, 1999;Smiciklas and Shiner, 2010;Storry et al, 2000;Zelevinsky et al, 2005), 1083 nm light was used to access the 4 He 2 3 P fine structure, with the prospect of obtaining an accurate value for the fine structure constant α. Assuming the QED theory of fine structure energies of an atomic system to be correct, a determination of α is possible by frequency measurements of these fine structure splittings, which are proportional to α 2 .…”

Section: Spectroscopic Measurements Of Atomic Properties a Metasmentioning

confidence: 99%

Cold and trapped metastable noble gases

et al. 2012

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We review experimental work on cold, trapped metastable noble gases. We emphasize the aspects which distinguish work with these atoms from the large body of work on cold, trapped atoms in general. These aspects include detection techniques and collision processes unique to metastable atoms. We describe several experiments exploiting these unique features in fields including atom optics and statistical physics. We also discuss precision measurements on these atoms including fine structure splittings, isotope shifts, and atomic lifetimes.

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Section: Spectroscopic Measurements Of Atomic Properties a Metasmentioning

confidence: 99%

Cold and trapped metastable noble gases

et al. 2012

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“…For many purposes the triplet metastable state of helium can be regarded as a second ground state, one far more accessible to experimenters than the 1 1 S state, so it has been the focus of much recent activity [2,3,4,5,6,7,8,9,40]. Continued advances in the theory of two-electron quantum electrodynamic (QED) and relativistic corrections have been spurred by improved experimental results, and particularly by the prospect of obtaining an improved value for the fine-structure constant from newly obtained and extremely accurate measurements of transitions between the triplet n=2 and n=3 states [6], assuming that present inconsistencies in the theoretical work can be resolved [7,8].…”

Section: Triplet Spectramentioning

confidence: 99%

“…Overall, experiment and theory are in reasonable agreement, although for many energy levels the theoretical uncertainties are smaller than the experimental ones. In a few important cases significant discrepancies arise, most notably for the fine structure of the 2 3 P state [2,3,4,5,6,7,8,9]. Of special interest is the ionization energy (IE) of the ground 1 1 S 0 state of 4 He, which provides a sensitive test of QED corrections for a two-electron system.…”

Section: Introductionmentioning

confidence: 99%

Prospects for precision measurements of atomic helium using direct frequency comb spectroscopy

et al. 2007

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Abstract. We analyze several possibilities for precisely measuring electronic transitions in atomic helium by the direct use of phase-stabilized femtosecond frequency combs. Because the comb is self-calibrating and can be shifted into the ultraviolet spectral region via harmonic generation, it offers the prospect of greatly improved accuracy for UV and far-UV transitions. To take advantage of this accuracy an ultracold helium sample is needed. For measurements of the triplet spectrum a magneto-optical trap (MOT) can be used to cool and trap metastable 2 3 S state atoms. We analyze schemes for measuring the two-photon 2 3 S → 4 3 S interval, and for resonant two-photon excitation to high Rydberg states, 2 3 S → 3 3 P → n 3 S, D. We also analyze experiments on the singlet-state spectrum. To accomplish this we propose schemes for producing and trapping ultracold helium in the 1 1 S or 2 1 S state via intercombination transitions. A particularly intriguing scenario is the possibility of measuring the 1 1 S → 2 1 S transition with extremely high accuracy by use of two-photon excitation in a magic wavelength trap that operates identically for both states. We predict a "triple magic wavelength" at 412 nm that could facilitate numerous experiments on trapped helium atoms, because here the polarizabilities of the 1 1 S, 2 1 S and 2 3 S states are all similar, small, and positive.

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“…[6,7] and references therein). Several experiments are now focusing on Helium and heliumlike ions 1s2p 3 P J fine structure [8][9][10][11][12], with the aim of providing a new determination of the fine structure constant and of checking higher-order effects in the calculations. In this case the theory is again a limiting factor.…”

mentioning

confidence: 99%

“…We thus see that the contribution of the self-energy to Eq. (2) depends only on contour integrals of the form (9), which are known analytically [32].…”

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confidence: 99%

Contribution of the screened self-energy to the Lamb shift of quasidegenerate states

2001

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Expressions for the effective Quantum Electrodynamics (QED) Hamiltonian due to self-energy screening (self-energy correction to the electron-electron interaction) are presented. We use the method of the two-time Green's function, which handles quasidegenerate atomic states. From these expression one can evaluate energy corrections to, e.g., 1s2p 3 P1 and 1s2p 1 P1 in helium and twoelectron ions, to all orders in Zα.In the last ten years, experiments in the spectroscopy of helium [1][2][3][4][5] have become two orders of magnitude more precise than the best theoretical energy level calculations available (see, e.g., Refs. [6,7] and references therein). Several experiments are now focusing on Helium and heliumlike ions 1s2p 3 P J fine structure [8][9][10][11][12], with the aim of providing a new determination of the fine structure constant and of checking higher-order effects in the calculations. In this case the theory is again a limiting factor. In this context a direct determination of all α 2 contributions to all order in Zα is necessary to improve reliability and accuracy of theoretical calculations (α being the fine structure constant, and Z the charge of the nucleus).A difficulty in the study of the (1s2p 1/2 ) 1 and (1s2p 3/2 ) 1 levels is that they are quasidegenerate for low and middle Z ions [13]; this precludes the use of the Gell-Man-Low and Sucher method [14,15] to evaluate QED energy shifts of atomic levels. In fact, this method has two important drawbacks: it does not handle quasidegenerate energy levels, and it leads to a difficult renormalization procedure when applied to degenerate states. (The latter problem has only been tackled up to second-order in α [16,17].)We use the method of the two-time Green's function [18][19][20], rigorously derived from QED (for the most detailed description of this method, see [21]). To the best of our knowledge, only the method recently proposed by Lindgren [22], closely modeled to multireference-state Many-body perturbation techniques, is designed to work for quasidegenerate states.We evaluate the contribution of the screened self-energy diagramsto quasidegenerate energy levels in heliumlike ions. Our results can be easily extended to ions with more than two electrons along lines similar to those found in [23]. First approximate evaluations of the contribution of these diagrams for isolated states in two-and three-electron ions were performed in Refs. [24][25][26][27]. Accurate calculations from the first principles of QED were accomplished in Refs. [28][29][30] for the ground state of heliumlike ions and in Refs. [31,32] for the 2s and 2p 1/2 states of lithiumlike ions. The other two α 2 corrections to the electron-electron interaction have also been calculated for isolated states in twoand three-electron ions: the vacuum-polarization screening [13,29,30,33,34], and the two-photon exchange diagrams [35][36][37][38]. In [13], the vacuum polarization screening for quasidegenerate states of heliumlike ions was evaluated as well. Some results for the direct contrib...

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Precision Microwave Measurement of the23P1−23

Cited by 58 publications

References 17 publications

Cold and trapped metastable noble gases

Cold and trapped metastable noble gases

Prospects for precision measurements of atomic helium using direct frequency comb spectroscopy

Contribution of the screened self-energy to the Lamb shift of quasidegenerate states

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