Higher-order effects on the precision of clocks of neutral atoms in optical lattices

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

“…The collision rate can be monitored by recording the number of quantum jumps during the absence of the 729-nm and 854-nm lasers. With < 1.0 × 10 −8 P a background pressure, about 0.022 (14) quantum jumps are observed per minute at different times (each procedure last 60 minutes, and repeated for 9 times), resulting in a maximum collision rate of 0.37(23)×10 −6 ms −1 . The corresponding contribution to the 3d 2 D 5/2 state lifetime is δτ 5/2 = 0.5(3) ms.…”

“…Since the existence of magic wavelengths for the 40 Ca + clock transition has been demonstrated both theoretically [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.…”

Calculation of higher-order corrections to the light shift of the $5s^2\, ^1\!S_0$--$5s5p\,^3\!P_0^o$ clock transition in Cd

“…Here k = ω/c, ω is the lattice laser wave frequency, c is the speed of light, and the factor 2 accounts for the superposition of forward and backward traveling along the x-axis waves. The atom-lattice interaction leads to the optical lattice potential for the atom that at |kx| ≪ 1 can be approximated as [2,6]…”

“…The Cd 5s 2 1 S 0 -5s5p 3 P o 0 transition has several desirable attributes for the development of a lattice clock. This clock has more than an order of magnitude smaller blackbody radiation (BBR) shift (a Stark shift resulting from the thermal radiation of the atoms environment, which is generally at 300 K temperature) in comparison with Sr and Yb [1][2][3]. The size of a BBR shift is a property of the specific atomic transition used as a frequency standard and an uncertainty in the BBR shift is known to be one of the limiting systematic uncertainties in the clock uncertainty budget [4,5].…”

Van der Waals molecules consisting of a zinc or cadmium atom interacting with an alkali-metal or alkaline-earth-metal atom

“…Here, the main focus has been put on the optical lattice clocks based on strontium [14,15,17], ytterbium [16,18], and mercury [19][20][21] atoms, however, recent proposals have brought attention to two other suitable candidates, zinc and cadmium atoms [22][23][24][25]. Optical lattice clocks based on group-IIB atoms, such as Zn, Cd, or Hg, have been shown to exhibit reduced susceptibility to the black body radiation (BBR) as compared to Sr-or Yb-based clocks [19-22, 24, 26].…”