Photodissociation of trapped $\mathrm{H}_{2}^{+}$ ions for REMPD spectroscopy

We present improved theoretical calculations of transition frequencies for the fundamental transitions (L = 0, v = 1) → (L = 0, v = 0) in the hydrogen molecular ions H + 2 and HD + with a relative uncertainty 4 · 10 −11 and for the two-photon transitions in the antiprotonic helium atom with a relative uncertainty 10 −10 . To do that, the one-loop self-energy correction of order α(Zα) 6 is derived in the two Coulomb center approximation, and numerically evaluated in the case of the aforementioned transitions. The final results also include a complete set of other spin-independent corrections of order mα 7 . The leading order corrections of α 2 ln 3 (Zα) −2 (Zα) 6 are also considered that allows to estimate a magnitude of yet uncalculated contributions.

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“…Here B 50 = −21.55447 (12), this contribution is valid for a bound electron in an arbitrary configuration of few pointlike Coulomb sources.…”

Section: B Other Contributionsmentioning

confidence: 99%

Theoretical transition frequencies beyond 0.1 ppb accuracy inH2+,HD+, and antiprotonic helium

2014

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“…Attempts to measure transitions in the (6,0) band have not yet resulted in accurate values [77]. Work is in progress to measure the spectrum of H + 2 in an ion trap [78], which is more difficult than probing HD + where electric dipole transitions are allowed, unlike for the homo-nuclear species. Alternatively, the spectroscopy of the H + 2 ion can be approached through measurements on the Rydberg states of the neutral hydrogen molecule, as had been done in the 1990s in measuring the hyperfine structure [79].…”

Section: Laser Precision Metrology Of Hd + and H +mentioning

confidence: 99%

Physics beyond the Standard Model from hydrogen spectroscopy

Ubachs

Koelemeij

Eikema

et al. 2016

Journal of Molecular Spectroscopy

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Spectroscopy of hydrogen can be used for a search into physics beyond the Standard Model. Differences between the absorption spectra of the Lyman and Werner bands of H 2 as observed at high redshift and those measured in the laboratory can be interpreted in terms of possible variations of the proton-electron mass ratio µ = m p /m e over cosmological history. Investigation of some ten of such absorbers in the redshift range z = 2.0 − 4.2 yields a constraint of |∆µ/µ| < 5 × 10 −6 at 3σ. Observation of H 2 from the photospheres of white dwarf stars inside our Galaxy delivers a constraint of similar magnitude on a dependence of µ on a gravitational potential 10 4 times as strong as on the Earth's surface. While such astronomical studies aim at finding quintessence in an indirect manner, laboratory precision measurements target such additional quantum fields in a direct manner. Laser-based precision measurements of dissociation energies, vibrational splittings and rotational level energies in H 2 molecules and their deuterated isotopomers HD and D 2 produce values for the rovibrational binding energies fully consistent with quantum ab initio calculations including relativistic and quantum electrodynamical (QED) effects. Similarly, precision measurements of high-overtone vibrational transitions of HD + ions, captured in ion traps and sympathetically cooled to mK temperatures, also result in transition frequencies fully consistent with calculations including QED corrections. Precision measurements of inter-Rydberg transitions in H 2 can be extrapolated to yield accurate values for level splittings in the H + 2 -ion. These comprehensive results of laboratory precision measurements on neutral and ionic hydrogen molecules can be interpreted to set bounds on the existence of possible fifth forces and of higher dimensions, phenomena describing physics beyond the Standard Model.

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“…Highly selective ion production was demonstrated for 0 ≤ v ≤ 6 and L = 1, 2 [35]; we choose L = 2 as these states have a simpler hyperfine structure (two sublevels as compared to five) [36]. The seven selected transitions are listed in Table I; spectroscopy of the (0, 2) → (1, 2) transition is being pursued at LKB Paris [36,37].…”

Section: And Hdmentioning

confidence: 99%

Hydrogen molecular ions for improved determination of fundamental constants

et al. 2016

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The possible use of high-resolution rovibrational spectroscopy of the hydrogen molecular ions H + 2 and HD+ for an independent determination of several fundamental constants is analyzed. While these molecules had been proposed for metrology of nuclear-to-electron mass ratios, we show that they are also sensitive to the radii of the proton and deuteron and to the Rydberg constant at the level of the current discrepancies colloquially known as the proton size puzzle. The required level of accuracy, in the 10 −12 range, can be reached both by experiments, using Doppler-free two-photon spectroscopy schemes, and by theoretical predictions. It is shown how the measurement of several well-chosen rovibrational transitions may shed new light on the proton-radius puzzle, provide an alternative accurate determination of the Rydberg constant, and yield new values of the proton-toelectron and deuteron-to-proton mass ratios with one order of magnitude higher precision. From Bohr's model of the atom to the advent of quantum electrodynamics (QED), precision spectroscopy of atomic hydrogen has played a key role in our understanding of matter and its interaction with light. Since the first measurement of the Lamb shift in 1947 [1, 2], the predictions of QED have been verified with an increasing level of accuracy which, together with stringent tests in other areas of physics, led to assume the validity of this theory and use it to extract the values of fundamental physical constants from experimental data [3]. Specifically, available data on the hydrogen (H) and deuterium (D) atoms are used to extract the Rydberg constant R ∞ and the charge radii of the proton (r p ) and deuteron (r d ). Data from electron-proton and electron-deuteron scattering experiments also contribute in this determination.Recently, the undisputed status of these results has been challenged by the measurement of the Lamb shift in muonic hydrogen [4,5]. The very precise value of r p deduced from this experiment is in strong disagreement with previous determinations. The discrepancy with the CODATA adjustment [6] amounts to 5.6σ, or to 4.5σ if only the H and D data are taken into account [3]. Similar discrepancies on the deuteron radius can be inferred through the very precise determination of r 2 d − r 2 p from the 1S-2S H/D isotopic shift [7]. Although many efforts have been undertaken in the last few years, no convincing solution of the "proton size puzzle" has been found so far (see [8] for a review). One of the possible explanations is that the error bars, both of hydrogen spectroscopy and scattering experiments [9] were underestimated. New scattering experiments are in preparation or underway, including electron-proton [10], electron-deuteron [11] and muon-proton scattering [12]. In atomic hydrogen, the 1S-3S(D) [13,14], 2S-2P [15], and 2S-4P [16] transitions are under study in order to cross-check and improve previous results. An independent determination of R ∞ , which is strongly correlated to r p and r d , is another way to shed new light on this prob...

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Photodissociation of trapped $\mathrm{H}_{2}^{+}$ ions for REMPD spectroscopy

Cited by 22 publications

References 27 publications

Theoretical transition frequencies beyond 0.1 ppb accuracy inH2+,HD+, and antiprotonic helium

Theoretical transition frequencies beyond 0.1 ppb accuracy inH2+,HD+, and antiprotonic helium

Physics beyond the Standard Model from hydrogen spectroscopy

Hydrogen molecular ions for improved determination of fundamental constants

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