Precision measurement of branching fractions ofBa138+: Testing many-body theories below the 1% level

Abstract

The branching fractions from the excited state 6P[/2 of singly charged barium ion has been measured with a precision 0.03% in an ion trap experiment. This measurement along with the known value of the upper state lifetime allowed the determination of the dipole matrix elements for the transitions P-S and P-D to below the 1% level. Therefore, it is now possible to compare the many-body calculations of these matrix elements at a level which is of significance to any parity-nonconservation experiment on barium ion. Moreover, these dipole matrix elements are the most significant contributors to the parity-violating matrix element between the S-D transition, contributing up to 90% to the total. Our results on the dipole matrix elements are 3.305 ± 0.014 a.u. and 3.042 ± 0.016 a.u. for the S-P and P-D transitions, respectively. Trapping and laser cooling of ions provide a perturbationfree environment to measure atomic state lifetime [1], light shift [2], branching ratio [3], and other fundamental properties of atoms with high precision [4], This leads to the use of trapped and laser cooled ions for quantum state manipulation [5,6], atomic clocks [7] and to study fundamental interac tions [8], The study of fundamental interactions via atomic properties include measurements of the Lamb shift [9], the parity-nonconservation (PNC) in atomic system [10], the conserved vector current hypothesis [ 11 ], the electron-electric dipole moment (e-EDM) [12], etc. As most of the original experiments have been carried out with atomic beams, they suffered from large systematic uncertainties due to limited control over the environment. These systematics are largely absent for stored atomic systems, and in addition, they provide long observation time. Therefore, in recent years, trapped and laser cooled ions have emerged as potential candidates to per form high precision experiments of fundamental importance like atomic parity violation [13,14] and e-EDM [8], Barium ion is particularly suitable for the investigation of PNC as was pointed out by Fortson [13] because of its large nuclear charge and ease of laser cooling and trapping.The best atomic PNC measurement performed so far is that of cesium with a precision of 0.3% [10]. However, the nuclear anapole moment obtained from this measurement shows a discrepancy with other nuclear data strongly suggesting the need to measure atomic PNC in other species in order to verify or to go beyond the standard model of particle physics. In this context, a number of experimental groups are pursuing an ion-trap-based atomic PNC experiment which has been proposed to be capable of limiting systematic uncertainty to below the 1% level. In addition to the experiment, one also needs the theoretical value of the parity-violating dipole matrix element with a similar precision. In principle, different variants ol the coupled cluster theory [15][16][17][18] are capable of providing such precision, provided the many-body wave functions are accurately known. Precision measurement of atomic properties of the lo...

Precision measurement of the branching fractions of the5pP1/22state inSrLikforman1, Tugayé2, Guibal3 et al. 2016Phys. Rev. A19180View full textAdd to dashboardCite

“…The same principle has been used more recently for the measurement of branching fractions of the 6s 2 S 1/2 state in 138 Ba + [15]. The main differences here, apart from the ion species, are the single-ion operation and the trap technology (micro-fabricated surface trap vs mechanically assembled macro traps).…”

“…By restricting ourselves to the case of heavier alkali-earth (i.e. species with D metastable states), these techniques have been recently applied to obtain precision measurements of spectroscopical quantities on laser-cooled 40 Ca + ions [9][10][11][12], 138 Ba + ions [13][14][15], and 88 Sr + ions [16][17][18][19]. In this paper we present the precision measurement of the branching fractions for the decay of the 5p 2 P 1/2 state of 88 Sr + .…”

An exacting transition probability measurement - a direct test of atomic many-body theories

“…However, knowledge of the low-lying electronic states with precision below one percent is a stringent requirement but up untill now the P 3/2 branching fraction is only known to about 5% precision mainly limited by the systematic uncertainties6. The other required properties like the P 1/2 branching fraction and dipole transition frequency have only been recently measured below 1% uncertainty78. In addition, this particular ion also has astrophysical importance due to its excessive abundance in certain main sequence stars which is popularly known as the barium puzzle 910.…”

Optimization of phonon dynamics protocols in ion traps

“…For definiteness, we consider a string of N positively charged ions with mass m confined using a linear Paul trap as shown in Fig. 1 [3,13,15,16]. The RF voltage provides a confinement along the radial direction whereas the axial confinement of ions is achieved by applying dc voltage at the end electrodes.…”

“…Since these ion trap systems can be used to emulate correlated models which harbors quantum phase transitions, they provide us with an unique opportunity to study the effect of local non-equilibrium dynamics near a quantum critical point [11,12]. Moreover, trapped ions are ideal system to test atomic physic at high precision [13] in a controlled and clean way which makes them ideal units for realization of a quantum computer.…”