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Minardi, F.; Bianchini, Giovanni; Pastor, P. Cancio; Giusfredi, G.; Pavone, Francesco S.; Inguscio, M.

doi:10.1103/physrevlett.82.1112

Cited by 74 publications

(61 citation statements)

References 28 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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“…Accurate microwave measurements [27,33,34] and high precision laser spectroscopy experiments [28,29,51,52] are usually performed on helium atomic beams. In contrast, we have made unsophisticated absorption measurements using a single free-running laser diode on helium gas in cells at room temperature, under the usual operating conditions for nuclear polarisation of 3 He by OP.…”

Section: Methodsmentioning

confidence: 99%

Magnetic field effects on the 1 083 nm atomic line of helium

Courtade¹,

Marion²,

Nacher³

et al. 2002

The European Physical Journal D - Atomic, Molecular and Optical

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Abstract. The structure of the excited 2 3 S and 2 3 P triplet states of 3 He and 4 He in an applied magnetic field B is studied using different approximations of the atomic Hamiltonian. All optical transitions (line positions and intensities) of the 1083 nm 2 3 S-2 3 P transition are computed as a function of B. The effect of metastability exchange collisions between atoms in the ground state and in the 2 3 S metastable state is studied, and rate equations are derived, for the populations these states in the general case of an isotopic mixture in an arbitrary field B. It is shown that the usual spin-temperature description remains valid. A simple optical pumping model based on these rate equations is used to study the B-dependence of the population couplings which result from the exchange collisions. Simple spectroscopy measurements are performed using a single-frequency laser diode on the 1083 nm transition. The accuracy of frequency scans and of measurements of transition intensities is studied. Systematic experimental verifications are made for B=0 to 1.5 T. Optical pumping effects resulting from hyperfine decoupling in high field are observed to be in good agreement with the predictions of the simple model. Based on adequately chosen absorption measurements at 1083 nm, a general optical method to measure the nuclear polarisation of the atoms in the ground state in an arbitrary field is described. It is demonstrated at B ∼0

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“…The evaluation of the reducible contribution follows steps similar to those used for the irreducible part. The contribution of diagrams (8) to the effective hamiltonian H (2) , which is given in Eq. (11), cancels a few terms of the contribution of the reducible diagram, as for diagonal matrix elements [32]; the total reducible contribution to Eq.…”

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confidence: 99%

“…[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.…”

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confidence: 99%

“…(13)] of the screened self-energy diagrams (1) to a finite-sized effective hamiltonian which acts on a few atomic energy levels (in the general case: quasidegenerate, fully degenerate or isolated); the eigenvalues of this hamiltonian give the QED prediction for the energy levels. We have also taken into account the contribution of the first-order diagrams (8) to the second-order hamiltonian (2).…”

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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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Measurement of the Helium23P0−23

Cited by 74 publications

References 28 publications

Cold and trapped metastable noble gases

Cold and trapped metastable noble gases

Magnetic field effects on the 1 083 nm atomic line of helium

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

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