Precise determination of the quadrupole transition matrix element ofCa+40via branching-fraction and lifetime measurements

Abstract

We report the first experimental determination of the 4s 2 S 1/2 ↔ 3d 2 D 5/2 quadrupole transition matrix element in 40 Ca + by measuring the branching ratio of the 3d 2 D 5/2 state decaying into the ground state 4s 2 S 1/2 and the lifetime of the 3d 2 D 5/2 state, using a technique of highly synchronized measurement sequence for laser control and highly efficient quantum state detection for quantum jumps. The measured branching ratio and improved lifetime are, respectively, 0.9992(80) and 1.1652(46) s, which yield the value of the quadrupole transition matrix element (in absolute value) 9.737(43) ea 2 0 with the uncertainty at the level of 0.44%. The measured quadrupole transition matrix element is in good agreement with the most precise many-body atomic structure calculations. Our method can be universally applied to measurements of transition matrix elements in single ions and atoms of similar structure. [11,12] and experimentally [13], all-optical trapped ion clocks are feasible to be realized in the foreseeable future. One important issue for building such kind of trap is to overcome large ac Stark shifts due to use of high optical power; thus it is necessary to take higher-order effects into account by knowing the corresponding high-order transition matrix elements [14]. In quantum information research, because of long coherence time of the ground and metastable states, selected quadrupole transitions for encoding a quantum bit of information are used to realize quantum logic techniques. In plasma physics, quadrupole transitions open an observational window into hot plasmas of low electron density [15]. In astrophysics, quadrupole transition lines provide information on structure and physical characteristics of interstellar clouds [16,17]. Moreover, electric quadrupole transitions can be used to study atomic parity-violation in heavy ions [18,19]. Finally, comparison between experimentally measured quadrupole transition matrix elements and their corresponding theoretical values can test sophisticated relativistic atomic many-body theories.In principle, dipole transition matrix elements in an atom or ion can be determined by measuring its ac Stark shifts when exposed to a light, using the concept of magic-zero (tune-out) wavelengths, such as the work on where g k = 6 and λ is the transition wavelength inÅ [1].Single 40 Ca + ion is first laser cooled and trapped in a miniature ring Paul trap. A high-efficiency quantum state detection method for fluorescence counting and a highly synchronized measurement sequence for laser conarXiv:1609.04177v1 [physics.atom-ph]

Radiative Transition Properties of Singly Charged Magnesium, Calcium, Strontium and Barium Ions

“…[35], whereas significant differences are found for the results in Ca + . But, a very important point to be noticed here is that our estimated quadrupole transition rate for the 3D 5/2 − 4S 1/2 transition in Ca + is in good agreement with the recent experimental results by Shao et al [81] within uncertainty limits. This provides strong evidence towards the accuracy of our results.…”

Combining experiments and relativistic theory for establishing accurate radiative quantities in atoms: The lifetime of the 2P3/2 state in CaMeir1, Sinhal2, Safronova3 et al. 2020Phys. Rev. A10160View full textAdd to dashboardCite

“…are the two transition rates connecting the D 5/2 "dark" state to the S 1/2 and D 3/2 "bright" states which give rise to a finite lifetime, τ D 5/2 = 1.1649(44) s [42], of this state. We experimentally verified this lifetime (with less precision) in our experiment to overrule spurious optical pumping effects.…”

“…Here, we exploit the high-fidelity control achievable over a single trapped ion to establish a novel method to measure the complete set of lifetimes, transition rates and reduced-dipole-matrix elements of atomic transitions using the complementarity of dispersive and absorptive light-matter interactions and by combining precise experimental measurements with high-level theoretical calculations. To illustrate our approach, we determine the lifetime of the P 3/2 state in 40 Ca + with high precision to τ P 3/2 = 6.639 (42) ns.…”

“…To summarize, measurements of transition rates and branching ratios were combined together with relativistic theory to achieve precision and to validate the accuracy of the lifetime of the (4p) 2 P 3/2 excited state of Ca + , τ P 3/2 = 6.639 (42) ns. The present method can be used to measure transition rates and lifetimes in many types of ionic, atomic and molecular systems both for single and ensembles of particles.…”

Laser ablation and two-step photo-ionization for the generation of 40Ca+

“…Trapped and laser-cooled ions are proven to be ideal candidates for optical frequency standards [1,2] and quantum information processing [3,4], due to their environmental isolation and long interrogation time. There are similar applications for the measurement of lifetimes and lifetime ratio [5][6][7][8][9], branching fractions [10,11], and transition matrix elements [12,13]. As detrimental destruction to vacuum conditions is inappreciable through accurate control by laser ablation, an ideal vacuum condition is beneficial to the experimental accuracy for limiting the effects of collisions and J mixing [14,15].…”