Recent developments in X-ray tests of quantum electrodynamicsThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at University of Windsor, Windsor, Ontario, Canada on 21–26 July 2008.

Chantler, Christopher T.; Kimpton, Justin A.

doi:10.1139/p09-019

Cited by 7 publications

(9 citation statements)

References 81 publications

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“…The absolute values we report here for the energy transitions are calibrated using the precise theoretical prediction of the M1 line energies which served as references (shifting the M1 energies would shift our values). Many of these energies only have a few-parts-per-million uncertainty, which puts them among the most precise spectroscopy results in highly charged ions [18,22,52,53]. This accuracy makes the measured energies sensitive to two-photon QED effects, mostly through the 1s 2s 3 S 1 level [21].…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, these measurements can be used as benchmarks for relativistic many-body calculations in three-and four-electron ions. A comparison between experiment and theory would test calculations of electronic correlation energies, which are often predicted with different values by different calculation methods [22], and of Auger shifts, for which to the best of our knowledge published results are limited to neutral atoms with a K, L, or M hole [5].…”

Section: Introductionmentioning

confidence: 99%

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High-accuracy x-ray line standards in the 3-keV region

et al. 2013

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A set of 14 high-accuracy x-ray transition energies in the 2.4-3.1 keV range is presented, which can be used as x-ray standards. They were measured in two-to four-electron sulfur, chlorine, and argon ions produced in an electron-cyclotron resonance ion source, using a single spherically bent crystal spectrometer. The results include the first measurement of six transitions and improve the accuracy of six other experimental values. These measurements considerably extend the set of high-accuracy x-ray energies reported for highly charged ions. Their relative uncertainties range from 1 to 10 ppm. Theory only reaches such a precision in one-and two-electron ions. Our results thus have two distinct applications. On the one hand, they test predictions in two-electron ions [Artemyev, Shabaev, Yerokhin, Plunien, and Soff, Phys. Rev. A 71, 062104 (2005)], at the precision level of some two-photon QED contributions. We observe an agreement with theory for most of the transitions. On the other hand, the three-and four-electron ion transitions provide new benchmark energies for the calculation of missing theoretical contributions, such as Auger shifts or electronic correlations. Spectra were analyzed with an x-ray tracing simulation that contains all the relevant physics of the spectrometer.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

High-accuracy x-ray line standards in the 3-keV region

et al. 2013

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“…Work on argon (Z = 18), for example, discussed evidence of dominating satellite line contamination under certain experimental conditions [36][37][38][39]. While it is believed that the associated uncertainty has been reduced dramatically in recent work on argon [9], detailed independent modeling is important to confirm relative positions and magnitudes of possible satellites which could affect the positions of the w-line [45,46]. In addition, new measurements in the unexplored range Z = 27 to Z = 31 would enable verification and systematic parameterization of apparent discrepancies with theory, pointing towards better ways of extending QED calculations beyond the two-body problem and into the extreme, high-field regime of highly charged ions.…”

Section: +mentioning

confidence: 99%

Testing Three-Body Quantum Electrodynamics with TrappedTi20+Ions: Evidence for aZ-dependent Divergence Between Experiment and Calculation

et al. 2012

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We report a new test of quantum electrodynamics (QED) for the w (1s2p 1 P1 → 1s 2 1 S0) X-ray resonance line transition energy in helium-like titanium. This measurement is one of few sensitive to two-electron QED contributions. Systematic errors such as Doppler shifts are minimised in our experiment by trapping and stripping Ti atoms in an Electron Beam Ion Trap (EBIT) and by applying absolute wavelength standards to calibrate the dispersion function of a curved-crystal spectrometer. We also report a more general systematic discrepancy between QED theory and experiment for the w transition energy in helium-like ions for Z > 20. When all of the data available in the literature forZ = 16 − 92 is taken into account, the divergence is seen to grow as approximately Z 3 with a statistical significance on the coefficient that rises to the level of five standard deviations. Our result for titanium alone, 4749.85(7) eV for the w-line, deviates from the most recent ab initio prediction by three times our experimental uncertainty and by more than ten times the currently estimated uncertainty in the theoretical prediction.PACS numbers: 31.30.jf, 12.20.Fv, 34.50.Fa, 32.30.Rj Quantum electrodynamics (QED) is a cornerstone of modern theoretical physics. New activity on this topic has been stimulated by the announcement of a five-sigma inconsistency between a 15 ppm (parts per million) measurement of an atomic transition frequency in muonic hydrogen [1] and independent measurements of the proton size, linked together by QED calculations. The high sensitivity of such a measurement to QED is derived in part from the large mass of the bound lepton which shrinks the orbital radius. Another way to reduce the orbital radius and study magnified QED effects is to measure transitions in highly charged ions of increasing Z. QED processes scale as various powers of Zα and significantly affect the quantum observable, namely transition energies. Moreover, in the high-Z range, some of the perturbative expansions fail, so that theoretical methods very different from those used for hydrogen are required. Since QED treatment of low-Z and high-Z systems are undertaken with significantly different starting points and mathematical techniques, precise measurements for ions in the mid-Z range will guide the long-pursued development of a unified computational methodology with very accurate predictions for the entire domain Z < 100 [2,3].Advances in QED theory have been sufficient that one can go beyond one-lepton systems (either free or bound) and explore the three-body quantum problem to high precision, including the investigation of helium-like * Electronic address: chantler@unimelb.edu.au atomic systems with two electrons bound to a nucleus. Here the two-electron QED contributions that are entirely absent in one-electron systems can be probed and compared to various theoretical formulations. In this work, we report a measurement of the strongest resonant transition 1s2p1 P 1 → 1s 2 1 S 0 in He-like Ti (Ti 20+ ), and present a divergence that is...

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“…Theory is that of Mohr [7] or Johnson and Soff [8]. [48]. The triangles (blue online) show all of the results published since 2003; these are the results of Chantler and coauthors (including the present results) that use the full dynamical diffraction theory in the analysis [31,32].…”

Section: Comparison To Measurements On Ions Of Similar Zmentioning

confidence: 77%

“…The review of Chantler and Kimpton [48] contains a discussion of some of the other potential problems in the experiments summarized in figure 2. The design of our experiment avoids many of these problems from the onset.…”

Section: Comparison To Measurements On Ions Of Similar Zmentioning

confidence: 99%

First measurement of Lyman alpha x-ray lines in hydrogen-like vanadium: results and implications for precision wavelength metrology and tests of QED

Gillaspy

Chantler

Paterson

et al. 2010

J. Phys. B: At. Mol. Opt. Phys.

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The first measurement of hydrogen-like vanadium x-ray Lyman alpha transitions has been made. The measurement was made on an absolute scale, fully independent of atomic structure calculations. Sufficient signal was obtained to reduce the statistical uncertainty to a small fraction of the total uncertainty budget. Potential sources of systematic error due to Doppler shifts were eliminated by performing the measurement on trapped ions. The energies for Ly α 1 (1s-2p 3/2) and Ly α 2 (1s-2p 1/2) are found to be 5443.95(25) eV and 5431.10(25) eV, respectively. These results are within approximately 1.5 σ (experimental) of the theoretical values 5443.63 eV and 5430.70 eV. The results are discussed in terms of their relation to the Lamb shift and the development of an x-ray wavelength standard based on a compact source of trapped highly charged ions.

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Recent developments in X-ray tests of quantum electrodynamicsThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at University of Windsor, Windsor, Ontario, Canada on 21–26 July 2008.

Cited by 7 publications

References 81 publications

High-accuracy x-ray line standards in the 3-keV region

High-accuracy x-ray line standards in the 3-keV region

Testing Three-Body Quantum Electrodynamics with TrappedTi20+Ions: Evidence for aZ-dependent Divergence Between Experiment and Calculation

First measurement of Lyman alpha x-ray lines in hydrogen-like vanadium: results and implications for precision wavelength metrology and tests of QED

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