Showing papers by "Cheng Chin published in 2001"

Measurement of an electron's electric dipole moment using Cs atoms trapped in optical lattices

Abstract: We propose to measure the electron's permanent electric dipole moment (EDM) using cesium atoms trapped in a sparsely populated, trichromatic, far blue-detuned three-dimensional (3D) optical lattice. In the proposed configuration, the atoms can be strongly localized near the nodes of the light field and isolated from each other, leading to a strong suppression of the detrimental effects of atom-atom and atom-field interactions. Three linearly polarized standing waves with different frequencies create an effectively linearly polarized 3D optical lattice and lead to a strong reduction of the tensor light shift, which remains a potential source of systematic error. Other systematics concerning external field instability and gradients and higher-order polarizabilities are discussed. Furthermore, auxiliary atoms can be loaded into the same lattices as effective ``comagnetometers'' to monitor various systematic effects, including magnetic-field fluctuations and imperfect electric-field reversal. We estimate that a sensitivity 100 times higher than the current upper bound for the electron's EDM of $4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}27}e\mathrm{cm}$ can be achieved with the proposed technique.

Determination of Cs-Cs interaction parameters using Feshbach spectroscopy

Abstract: We measure high-resolution Feshbach resonance spectra for ultracold cesium atoms colliding in different hyperfine and magnetic sublevels More than 25 Feshbach resonances are observed for magnetic fields below 230 G in the elastic and inelastic ground state collision cross sections, as well as in the cross section for light-assisted collisions From these spectra a consistent set of ground state molecular interaction parameters for cesium is extracted, including singlet and triplet scattering lengths of A(s) = (280 +/- 10)alpha (0) and A(t) = (2400 +/- 100)alpha (0), a van der Waals coefficient C-6 (6890 +/- 35) au, as well as the strength of the indirect spin-spin coupling This set of parameters allows for the first time a complete characterization of cesium's ultracold-collision properties (C) 2001 Academie des sciences/Editions scientifiques et medicales Elsevier SAS

Laser cooling: Beyond optical molasses and beyond closed transitions

Abstract: We present a simple and general optical cooling method based on 3D degenerate Raman sideband cooling with adiabatic release that goes significantly beyond the density and temperature limitations of optical molasses. In 10 ms we cool a sample of 3×108 cesium atoms to a temperature of 330 nK at a density of 1.1×1011 cm−3, which corresponds to a phase-space density nλdB3=1/500.We further propose to cool atoms or molecules inside an optical cavity that enhances the scattering of blue-detuned photons and show that the dissipative mechanism can be viewed as a cavity-induced generalized Doppler cooling. Since the cooling depends on the atom’s internal level structure only through the photon scattering rate, cavity Doppler cooling is applicable to particles that do not possess a closed optical transition, which may allow one to extend laser cooling to a greater class of atoms or molecules. Large samples are cooled at the same rate as single atoms if the effect of one atom on the cavity resonance frequency is smal...