Precision spectroscopy of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mn>3</mml:mn><mml:mi>s</mml:mi><mml:mtext>−</mml:mtext><mml:mn>3</mml:mn><mml:mi>p</mml:mi></mml:mrow></mml:math>fine-structure doublet in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mtext>Mg</mml:mtext></mml:mrow><mml:mo>+</mml:mo></mml:msup></mml:mrow></mml:math>

Batteiger, Valentin; Knünz, Sebastian; Herrmann, M. G.; Saathoff, G.; Schüssler, H. A.; Bernhardt, Birgitta; Wilken, Tobias; Holzwarth, Ronald; Hänsch, Theodor W.; Udem, Thomas

doi:10.1103/physreva.80.022503

Cited by 60 publications

(68 citation statements)

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“…For the Mg i, Mg ii, and Fe ii lines (except for λ1608 Å), we adopted the wavelengths from Aldenius (2009). The wavelengths of the Mg i line from Salumbides et al (2006), the Mg ii lines from Batteiger et al (2009), and the Fe ii lines from Nave & Sansonetti (2010) all are shorter by < ∼ 0.2 mÅ than the corresponding values from Aldenius (2009). In the velocity space, the shifts between these wavelength scales are in the range of 3.5 m s −1 to 26 m s −1 , but because all wavelengths are shifted in the same direction, the relative shifts between the lines that we compare in our analysis do not exceed 15 m s −1 , which is well below the measurement errors.…”

Section: Discussionmentioning

confidence: 99%

First measurement of Mg isotope abundances at high redshifts and accurate estimate of Δα/α

Agafonova

Molaro

Levshakov

et al. 2011

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Aims. Abundances of the Mg isotopes 24 Mg, 25 Mg, and 26 Mg can be used to test models of chemical enrichment of interstellar/intergalactic gas clouds. Additionally, because the position of the Mg ii λλ2796, 2803 Å lines is often taken as a reference in computations of possible changes of the fine-structure constant α, it should be clarified to which extent these lines are affected by isotopic shifts. Methods. We use a high-resolution spectrum (pixel size ≈1.3 km s −1 ) of the quasar HE0001-2340 observed with the UVES/VLT to measure Mg isotope abundances in the intervening absorption-line systems at high redshifts. Line profiles are prepared taking into account possible shifts between the individual exposures. In the line-fitting procedure, the lines of each ion are treated independently. Because of the unique composition of the selected systems -the presence of several transitions of the same ion -we can test the local accuracy of the wavelength scale calibration, which is the main source of errors in the sub-pixel line position measurements. Results. In the system at z abs = 0.45, which is probably a fragment of the outflow caused by SN Ia explosion of highmetallicity white dwarf(s), we measured velocity shifts of Mg ii and In the systems at z abs = 1.58 and z abs = 1.65 enriched by AGB-stars we find only upper limits on the content of heavy Mg isotopes ( 25 Mg+ 26 Mg)/ 24 Mg < ∼ 0.7 and ( 25 Mg+ 26 Mg)/ 24 Mg < ∼ 2.6, respectively. At z abs = 1.58, we also put a strong constraint on a putative variation of α: Δα/α = (−1.5 ± 2.6) × 10 −6 , which is one of the most stringent limits obtained from optical spectra of QSOs. We reveal that the wavelength calibration in the range above 7500 Å is subject to systematic wavelength-dependent drifts.

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Section: Discussionmentioning

confidence: 99%

First measurement of Mg isotope abundances at high redshifts and accurate estimate of Δα/α

Agafonova

Molaro

Levshakov

et al. 2011

A&A

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“…We use the most recent and most precise MgII laboratory wavelengths (Batteiger et al 2009), and the most recent and most precise FeII wavelengths (Nave 2012). In generating model absorption profiles, we use the 25 MgII 3s to 3p hyperfine structures (see Appendix A).…”

Section: Atomic Datamentioning

confidence: 99%

Artificial intelligence applied to the automatic analysis of absorption spectra. Objective measurement of the fine structure constant.

Bainbridge

Webb

2017

Mon. Not. R. Astron. Soc.

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A new and automated method is presented for the analysis of high-resolution absorption spectra. Three established numerical methods are unified into one "artificial intelligence" process: a genetic algorithm (GVPFIT); non-linear least-squares with parameter constraints (VPFIT); and Bayesian Model Averaging (BMA).The method has broad application but here we apply it specifically to the problem of measuring the fine structure constant at high redshift. For this we need objectivity and reproducibility. GVPFIT is also motivated by the importance of obtaining a large statistical sample of measurements of ∆α/α. Interactive analyses are both time consuming and complex and automation makes obtaining a large sample feasible.In contrast to previous methodologies, we use BMA to derive results using a large set of models and show that this procedure is more robust than a human picking a single preferred model since BMA avoids the systematic uncertainties associated with model choice.Numerical simulations provide stringent tests of the whole process and we show using both real and simulated spectra that the unified automated fitting procedure out-performs a human interactive analysis. The method should be invaluable in the context of future instrumentation like ESPRESSO on the VLT and indeed future ELTs.We apply the method to the z abs = 1.8389 absorber towards the z em = 2.145 quasar J110325-264515. The derived constraint of ∆α/α = 3.3±2.9×10 −6 is consistent with no variation and also consistent with the tentative spatial variation reported in Webb et al. (2011) andKing et al. (2012).

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“…Figure 1 shows the experimental setup (see also [6,9]). A 24 Mg þ ion is stored in a linear rf ion trap which consists of four symmetrically arranged tungsten rods, each 80 mm long and 2 mm in diameter.…”

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Injection Locking of a Trapped-Ion Phonon Laser

et al. 2010

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We report on injection locking of optically excited mechanical oscillations of a single, trapped ion. The injection locking dynamics are studied by analyzing the oscillator spectrum with a spatially selective Fourier transform technique and the oscillator phase with stroboscopic imaging. In both cases we find excellent agreement with theory inside and outside the locking range. We attain injection locking with forces as low as 5ð1Þ Â 10 À24 N so this system appears promising for the detection of ultraweak oscillating forces. [5]. In this Letter we report injection locking of an almost ultimately simple and well-controlled system, the motion of a single, harmonically bound ion.A Mg þ ion, held in a linear rf trap, is addressed by two laser beams tuned below (red detuned) and above (blue detuned) an atomic resonance, respectively. While the reddetuned laser damps the motion of the ion, the bluedetuned laser provides gain by amplifying an existing motion. For appropriate settings of laser detunings and intensities, regenerative oscillations with a stable amplitude start from noise. The forces due to the laser beams saturate as periodic Doppler shifts are induced by the ion motion. Recently, we could show that the amplification is due to the stimulated generation of vibrational quanta (phonons) and that the system represents a mechanical analogue of an optical laser, a phonon laser [6].We study the action of a weak, harmonic rf signal tuned close to the motional resonance on the dynamics of this oscillator using two different techniques, which both rely on the good spatial and temporal resolution of our imaging system. With the first method, a spatially selective Fourier transform technique, we obtain the motional spectrum of the oscillator. The second method, stroboscopic imaging, allows us to retrieve the phase of the ion relative to the drive. All our observations agree very well with theory, further substantiate the analogy to an optical laser, and extend its applicability. Our analysis reveals that we attain injection locking with minute forces as small as 5(1) yN (yocto 10 À24 ). This great sensitivity might allow the detection of nuclear spin flips of single atomic or molecular ions.Injection locking is a well-understood phenomenon [7,8]. Let us review some basic features for later reference: consider an oscillator of free-running frequency ! 0 , mass m, and linewidth . A weak oscillation induced by an injected auxiliary rf signal of frequency ! i and voltage U i is amplified by the blue-detuned laser. The gain of this auxiliary frequency component is proportional to [7] jgð Þj 2 % 2 2( 1) for sufficiently large detunings ¼ ! i À ! 0 . As the detuning decreases, the injected signal takes up more of the limited gain available from the blue-detuned laser. The gain at the free oscillation reduces accordingly; once it drops below threshold only the oscillation at ! i prevailsthe oscillator is injection locked to the external source [7]. Assuming the injected signal is weak, the total oscillation amplitude of the...

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Precision spectroscopy of the3s−3pfine-structure doublet inMg+

Cited by 60 publications

References 50 publications

First measurement of Mg isotope abundances at high redshifts and accurate estimate of Δα/α

First measurement of Mg isotope abundances at high redshifts and accurate estimate of Δα/α

Artificial intelligence applied to the automatic analysis of absorption spectra. Objective measurement of the fine structure constant.

Injection Locking of a Trapped-Ion Phonon Laser

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