Measurement of the lifetimes of the lowest<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi>P</mml:mi><mml:mn>1</mml:mn><mml:none /><mml:mprescripts /><mml:none /><mml:mn>3</mml:mn></mml:mmultiscripts></mml:math>state of neutral Ba and Ra

We present an exhaustive overview of optical absorption and laser-induced fluorescence lines of Ba atoms in liquid and solid helium matrices in visible and near-infrared spectral ranges. Due to the increased density of isolated atoms, we have found a large number of spectral lines that were not observed in condensed helium matrices before. We have also measured the lifetimes of metastable states. The lowest 3 D 1 metastable state has lifetime of 2.6 s and can be used as an intermediate state in two-step excitations of high-lying states. Various matrix-induced radiationless population transfer channels have been identified.

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“…The obtained lifetime of the 6s6p 3 P 1 state is found to be τ = 1.20(1) μs, which is 10% smaller than in the free atom τ = 1.345 (14) μs [23].…”

Section: Fluorescence From the Sr Atommentioning

confidence: 95%

Spectroscopy of barium atoms in liquid and solid helium matrices

2011

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“…These nuclei are all unstable, but their lifetimes are long enough to allow interferometry over time scales ∼ 1 s. The use of such highly radioactive materials in an experiment is of course non trivial. However, we note that Radium 225 is currently being used in an atom interferometer setup that is aimed at searching for the static dipole moment of the neutron [42]. The use of Radium 225 in [42] is precisely motivated by the large enhancement in its Schiff moment relative to that of Mercury, which also helps the search of static nuclear dipole moments.…”

Section: Overview Of the Detection Methodsmentioning

confidence: 99%

Axion dark matter detection with cold molecules

2011

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Current techniques cannot detect axion dark matter over much of its parameter space, particularly in the theoretically well-motivated region where the axion decay constant f a lies near the GUT and Planck scales. We suggest a novel experimental method to search for QCD axion dark matter in this region. The axion field oscillates at a frequency equal to its mass when it is a component of dark matter. These oscillations induce time varying CP-odd nuclear moments, such as electric dipole and Schiff moments. The coupling between internal atomic fields and these nuclear moments gives rise to time varying shifts to atomic energy levels. These effects can be enhanced by using elements with large Schiff moments such as the light Actinides, and states with large spontaneous parity violation, such as molecules in a background electric field. The energy level shift in such a molecule can be ∼ 10 −24 eV or larger. While challenging, this energy shift may be observable in a molecular clock configuration with technology presently under development. The detectability of this energy shift is enhanced by the fact that it is a time varying shift whose oscillation frequency is set by fundamental physics and is therefore independent of the details of the experiment. This signal is most easily observed in the sub-MHz range, allowing detection when f a is 10 16 GeV, and possibly as low as 10 15 GeV. A discovery in such an experiment would not only reveal the nature of dark matter and confirm the axion as the solution to the strong CP problem, it would also provide a glimpse of physics at the highest energy scales, far beyond what can be directly probed in the laboratory.

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“…The observed linewidths of the loading spectra are 100 MHz FWHM, which is much wider than the 50 kHz natural linewidth of the 791 nm intercombination line [24], the estimated transit broadening of ~1 MHz, and the power broadened linewidth of 7.6 MHz. Although the 791 nm laser beam is aligned orthogonal to the axis of the atomic beam to minimize Doppler broadening, there is residual Doppler broadening due to the divergence of the atomic beam (δθ~0.3 rad), Using the most probable velocity of the atomic beam v = 320 m/s for an oven temperature of 300 ºC yields an estimate of the Doppler broadening of 102 MHz FWHM, in good agreement with the observed linewidth.…”

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confidence: 97%

Photoionization and photoelectric loading of barium ion traps

et al. 2007

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Simple and effective techniques for loading barium ions into linear Paul traps are demonstrated. Two-step photoionization of neutral barium is achieved using a weak intercombination line (6s 2 1 S 0 ↔ 6s6p 3 P 1 , λ = 791 nm) followed by excitation above the ionization threshold using a nitrogen gas laser (λ = 337 nm). Isotopic selectivity is achieved by using a near Doppler-free geometry for excitation of the triplet 6s6p 3 P 1 state. Additionally, we report a particularly simple and efficient trap loading technique that employs an inexpensive UV epoxy curing lamp to generate photoelectrons.PACS numbers: 32.80. Fb, 32.80.Pj, 79.60.Fr Ion traps are an important technology for precision metrology with applications to frequency and time standards [1] and tests of fundamental physics [2,3]. Ion traps also represent a leading candidate for quantum information processors and quantum simulators [4].Ion traps are typically loaded by ionizing neutral atoms in the trapping region using electron beam bombardment. Recently, several groups [5][6][7][8][9][10][11][12] have demonstrated optical-based techniques for creating the ions that employ photoionization (PI) of neutral atoms. These techniques offer much greater loading efficiencies compared with electron impact ionization and also minimize charge build-up on insulating surfaces from the electron beam. Charge build-up can destabilize the trap and is thought to contribute to micromotion heating [13]. Minimizing charge build-up is particularly important for loading smaller chip-based ion traps [14] as well as for ion cavity QED applications that require dielectric mirrors in close proximity to the ion trap [15,16]. We are particularly motivated to reach the cavity QED strong coupling regime with trapped ions, which requires mirror separations of < 1 mm for strong optical transitions. Photoionization loading also offers the advantage of isotope selective loading [17] and simplifies the ion trap apparatus by eliminating the necessity of the electron beam.In this report, we demonstrate photoionization loading of a barium ion trap. Previous work in photoionization ion trap loading with Ca, Mg, Sr, Yb and Cd [5][6][7][8][9][10][11][12] have all employed two-step excitation beginning with a strong dipole allowed S-P transition. In our case, the strong transition ( 1 S 0 → 1 P 1 , λ = 553 nm) requires an expensive dye laser, and instead we employ a weak intercombination transition that can be excited with a simple extended cavity diode laser (ECDL). We show the isotopic selectivity of the photoionization loading technique and measure the loading rate under a variety of experimental conditions. Additionally, we demonstrate a particularly simple loading technique that employs a UV halogen lamp to generate photo-electrons which then ionize the neutral atoms. Although this latter technique relies on electron bombardment, and hence can lead to charge build-up, it obviates the need for an electron beam source.The relevant atomic structures of neutral and singly ionized Ba can be se...

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Measurement of the lifetimes of the lowestP13state of neutral Ba and Ra

Cited by 39 publications

References 17 publications

Spectroscopy of barium atoms in liquid and solid helium matrices

Spectroscopy of barium atoms in liquid and solid helium matrices

Axion dark matter detection with cold molecules

Photoionization and photoelectric loading of barium ion traps

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