Browsing by Author "Mickelson, P.G."
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Item Absorption Imaging of Ultracold Neutral Plasmas(2005-04) Simien, C.E.; Chen, Y.C.; Gupta, P.; Laha, S.; Martinez, Y.N.; Mickelson, P.G.; Nagel, S.B.; Killian, T.C.Item Bose-Einstein Condensation of 84Sr(American Physical Society, 2009) Martinez de Escobar, Y.N.; Mickelson, P.G.; Yan, M.; DeSalvo, B.J.; Nagel, S.B.; Killian, T.C.We report Bose-Einstein condensation of Sr84 in an optical dipole trap. Efficient laser cooling on the narrow intercombination line and an ideal s-wave scattering length allow the creation of large condensates (N0∼3×105) even though the natural abundance of this isotope is only 0.6%. Condensation is heralded by the emergence of a low-velocity component in time-of-flight images.Item Bose-Einstein condensation of 88Sr through sympathetic cooling with 87Sr(2010-05-05) Mickelson, P.G.; Martinez de Escobar, Y.N.; Yan, M.; DeSalvo, B.J.; Killian, T.C.We report Bose-Einstein condensation of Sr88, which has a small, negative s-wave scattering length (a88=−2a0). We overcome the poor evaporative cooling characteristics of this isotope by sympathetic cooling with Sr87 atoms. Sr87 is effective in this role despite the fact that it is a fermion because of the large ground-state degeneracy arising from a nuclear spin of I=9/2, which reduces the impact of Pauli blocking of collisions. We observe a limited number of atoms in the condensate (Nmax≈104) that is consistent with the value of a88 and the optical dipole trap parameters.Item Degenerate Fermi Gas of 87Sr(2010-07-13) DeSalvo, B.J.; Yan, M.; Mickelson, P.G.; Martinez de Escobar, Y.N.; Killian, T.C.We report quantum degeneracy in a gas of ultracold fermionic Sr87 atoms. By evaporatively cooling a mixture of spin states in an optical dipole trap for 10.5 s, we obtain samples well into the degenerate regime with T/TF=0.26+0.05−0.06. The main signature of degeneracy is a change in the momentum distribution as measured by time-of-flight imaging, and we also observe a decrease in evaporation efficiency below T/TF∼0.5.Item Electron Screening and Kinetic-Energy Oscillations in a Strongly Coupled Plasma(2004-12-20) Chen, Y.C.; Simien, C.E.; Laha, S.; Gupta, P.; Martinez, Y.N.; Mickelson, P.G.; Nagel, S.B.; Killian, T.C.; Rice Quantum InstituteItem Inelastic and elastic collision rates for triplet states of ultracold strontium(2009-06-05) Traverso, A.; Chakraborty, R.; Martinez de Escobar, Y.N.; Mickelson, P.G.; Nagel, S.B.; Yan, M.; Killian, T.C.Item Kinetic energy oscillations in annular regions of ultracold neutral plasmas(2006) Laha, S.; Chen, Y.C.; Gupta, P.; Simien, C.E.; Martinez, Y.N.; Mickelson, P.G.; Nagel, S.B.; Killian, T.C.; Rice Quantum InstituteItem Numerical modeling of collisional dynamics of Sr in an optical dipole trap(American Physical Society, 2011) Yan, M.; Chakraborty, R.; Mazurenko, A.; Mickelson, P.G.; Martinez de Escobar, Y.N.; DeSalvo, B.J.; Killian, T.C.We describe a model of inelastic and elastic collisional dynamics of atoms in an optical dipole trap that utilizes numerical evaluation of statistical mechanical quantities and numerical solution of equations for the evolution of number and temperature of trapped atoms. It can be used for traps that possess little spatial symmetry and when the ratio of trap depth to sample temperature is relatively small. We compare simulation results with experiments on Sr88 and Sr84, which have well-characterized collisional properties.Item Photoassociative Spectroscopy at Long Range in Ultracold Strontium(2005-03-03) Nagel, S.B.; Mickelson, P.G.; Saenz, A.D.; Martinez, Y.N.; Chen, Y.C.; Killian, T.C.; Pellegrini, P.; Cote, R.; Rice Quantum InstituteItem Spectroscopic Determination of the s-Wave Scattering Lengths of 86Sr and 88Sr(2005-11-22) Mickelson, P.G.; Martinez, Y.N.; Saenz, A.D.; Nagel, S.B.; Chen, Y.C.; Killian, T.C.; Pellegrini, P.; Cote, R.Item Two-photon photoassociative spectroscopy of ultracold 88Sr(2008-12-10) Martinez de Escobar, Y.N.; Mickelson, P.G.; Pellegrini, P.; Nagel, S.B.; Traverso, A.; Yan, M.; Cote, R.; Killian, T.C.Item Using Absorption Imaging to Study Ion Dynamics in an Ultracold Neutral Plasma(2004-04-06) Simien, C.E.; Chen, Y.C.; Gupta, P.; Laha, S.; Martinez, Y.N.; Mickelson, P.G.; Nagel, S.B.; Killian, T.C.; Rice Quantum Institute