Radiative Lifetime Measurement of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">Ba</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>Metastable<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="italic">D</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:ms

Yu, Nan; Nagourney, Warren; Dehmelt, Hans

doi:10.1103/physrevlett.78.4898

Cited by 59 publications

(64 citation statements)

References 10 publications

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“…These calculations are Excitation energy τ UCCSD(T) 4789 81.01 CCSD(T) [14] 4809 87.06 Dzuba et al [15] 4411 81.5 Guet et al [16] 4688 83.7 Experiment [17] 4874 79±4.6…”

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confidence: 99%

Relativistic unitary coupled cluster theory and applications

Sur

Chaudhuri

Sahoo

et al. 2008

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

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We present the first formulation and application of relativistic unitary coupled cluster theory to atomic properties. The remarkable features of this theory are highlighted, and it is used to calculate the lifetimes of 5 2 D 3/2 and 6 2 P 3/2 states of Ba + and P b + respectively. The results clearly suggest that it is very well suited for accurate ab initio calculations of properties of heavy atomic systems.PACS numbers: 31.15. Ar, 31.15.Dv, 31.25.Jf, 32.10.Fn There have been a number of attempts to modify coupled-cluster (CC) theory [1], despite its spectacular success in elucidating the properties of a wide range of many-body systems [1,2,3,4,5]. One interesting case in point is unitary coupled-cluster (UCC) theory which was first proposed by Kutzelnigg [6]. In this theory, the effective Hamiltonian is Hermitian by construction and the energy which is the expectation value of this operator in the reference state is unlike in CC theory, an upper bound to the ground state energy [5]. Another attractive feature of this theory which we shall discuss later is that at a given level of approximation it incorporates certain higher order excitations that are not present in CC theory. Furthermore, it is well suited for the calculation of properties where core relaxation effects are important [7,8]. In spite of the aforementioned advantages, there have been relatively few studies based on this method [9,10]. This work is the first relativistic formulation of unitary coupled cluster (UCC) theory and also the first application of this theory to atomic properties. In this letter, we first present the formal aspects of relativistic UCC theory and then apply it to calculate the lifetimes of the 5 2 D 3/2 and 6 2 P 3/2 states of Ba + and P b + respectively; which depend strongly on both relativistic and correlation effects. The comparison of the results of these calculations with accurate experimental data would constitute an important test of this theory.The exact wave function for a closed shell state in CC theory is obtained by the action of the operator exp(T ) on the reference state |Φ . However, in UCC theory [10], it is written aswhere σ = T − T † ; and T and T † are the excitation and deexcitation operators respectively. σ is clearly antiHermitian, since σ † = −σ. Using this unitary ansatz for the correlated wave function, the relativistic UCC equation in the Dirac-Coulomb approximation can be written aswhere H is the Dirac-Coulomb HamiltonianUsing the normal ordered Hamiltonian, Eq.(2) can be rewritten aswhere the normal ordered Hamiltonian is defined as H N = H − Φ| H |Φ and ∆E = E − Φ| H |Φ . . The choice of the operator σ makes the effective Hamiltonian H N = exp(−σ)H N exp(σ) Hermitian.The effective Hamiltonian is expressed by the Hausdorff expansion in CC theory as

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“…These calculations are Excitation energy τ UCCSD(T) 4789 81.01 CCSD(T) [14] 4809 87.06 Dzuba et al [15] 4411 81.5 Guet et al [16] 4688 83.7 Experiment [17] 4874 79±4.6…”

mentioning

confidence: 99%

Relativistic unitary coupled cluster theory and applications

Sur

Chaudhuri

Sahoo

et al. 2008

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

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“…The S 1/2 →P 1/2 transition is excited using a commercial doubled diode laser system (Toptica SHG-100) operating at 493 nm. The P 1/2 state can also decay into the metastable D 3/2 state (τ = 80 s) [20] with a 25% branching ratio [21], and a commercial ECDL (Toptica DL100) at 650 nm is used to repump the population out of this state. A weak magnetic field (1 G) is applied in order to prevent the formation of time-independent dark states in the D 3/2 Zeeman manifold [22].…”

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confidence: 99%

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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“…Singly ionized barium, Ba-II, has been very well studied in ion traps as a candidate system for optical clocks [6,44,45]. Ba-II has a single electron outside of a closed shell of inner electrons and behaves very much like the hydrogenic alkali earth elements of the first column of the periodic table.…”

Section: Ba-ii Spectroscopymentioning

confidence: 99%

“…An excited ion in the 6 2 P 1/2 state will transition to the metastable 5 2 D 3/2 state with 25% probability. The metastable state has a 79.8 ± 4.6 s lifetime [45], so fluorescence experiments require both an excitation laser at 493 nm and a "clean-up" or repump laser at 650 nm to prevent optical pumping into the metastable "dark" state. It should be noted that These properties apply to barium ions in vacuum and may not necessarily apply to barium ions in gas.…”

Section: Ba-ii Spectroscopymentioning

confidence: 99%

Single Ion Trapping for the Enriched Xenon Observatory

Waldman¹

2006

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In the last decade, a variety of neutrino oscillation experiments have established that there is a mass difference between neutrino flavors, without determining the absolute neutrino mass scale. The Enriched Xenon Observatory for neutrinoless double beta decay (EXO) will search for the rare decays of xenon to determine the absolute value of the neutrino mass. The experiment uses a novel technique to minimize backgrounds, identifying the decay daughter product in real time using single ion spectroscopy. Here, we describe single ion trapping and spectroscopy compatible with the EXO detector. We extend the technique of single ion trapping in ultrahigh vacuum to trapping in xenon gas. With this technique, EXO will achieve a neutrino mass sensitivity of m ν .010 eV.v vi

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Radiative Lifetime Measurement of theBa+MetastableD3/2

Cited by 59 publications

References 10 publications

Relativistic unitary coupled cluster theory and applications

Relativistic unitary coupled cluster theory and applications

Photoionization and photoelectric loading of barium ion traps

Single Ion Trapping for the Enriched Xenon Observatory

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