78 research outputs found

    Lattice-induced non-adiabatic frequency shifts in optical lattice clocks

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    We consider the frequency shift in optical lattice clocks which arises from the coupling of the electronic motion to the atomic motion within the lattice. For the simplest of 3-D lattice geometries this coupling is shown to only affect clocks based on blue-detuned lattices. We have estimated the size of this shift for the prospective strontium lattice clock operating at the 390 nm blue-detuned magic wavelength. The resulting fractional frequency shift is found to be on the order of 101810^{-18} and is largely overshadowed by the electric quadrupole shift. For lattice clocks based on more complex geometries or other atomic systems, this shift could potentially be a limiting factor in clock accuracy.Comment: 5 page

    Experimental constraints on the polarizabilities of the 6s^2 1S0 and 6s6p 3P0 states of Yb

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    We utilize accurate experimental data available in the literature to yield bounds on the polarizabilities of the ground and first excited states of atomic Yb. For the 6s^2 1S0 ground state, we find the polarizability alpha to be constrained to 134.4<alpha<144.2 in atomic units, while for the 6s6p 3P0 excited state we find 280.1<alpha<289.9. The uncertainty in each of these values is 1.0. These constraints provide a valuable check for ab initio and semi-empirical methods used to compute polarizabilities and other related properties in Yb.Comment: 7 pages, 1 figur

    Sensitivity to alpha-variation in ultracold atomic-scattering experiments

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    We present numerical calculations for cesium and mercury to estimate the sensitivity of the scattering length to the variation of the fine structure constant alpha. The method used follows ideas Chin and Flambaum [Phys. Rev. Lett. 96, 230801 (2006)], where the sensitivity to the variation of the electron to proton mass ratio, beta, was considered. We demonstrate that for heavy systems, the sensitivity to variation of alpha is of the same order of magnitude as to variation of beta. Near narrow Feshbach resonances the enhancement of the sensitivity may exceed nine orders of magnitude.Comment: 5 pages, 1 figur

    Convergence of all-order many-body methods: coupled-cluster study for Li

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    We present and analyze results of the relativistic coupled-cluster calculation of energies, hyperfine constants, and dipole matrix elements for the 2s2s, 2p1/22p_{1/2}, and 2p3/22p_{3/2} states of Li atom. The calculations are complete through the fourth order of many-body perturbation theory for energies and through the fifth order for matrix elements and subsume certain chains of diagrams in all orders. A nearly complete many-body calculation allows us to draw conclusions on the convergence pattern of the coupled-cluster method. Our analysis suggests that the high-order many-body contributions to energies and matrix elements scale proportionally and provides a quantitative ground for semi-empirical fits of {\em ab inito} matrix elements to experimental energies.Comment: 4 pages, 3 figure