Direct spectroscopy of the 2^2S1/2−2_{1/2}-^2P1/2_{1/2} and 2^2D3/2−2_{3/2}-^2P1/2_{1/2} transitions and observation of micromotion modulated spectra in trapped \Ca

We present an experimental scheme to perform spectroscopy of the $^2$S$_{1/2}-^2$P$_{1/2}$ and $^2$D$_{3/2}-^2$P$_{1/2}$ transitions in \Ca. By rapidly switching lasers between both transitions, we circumvent the complications of both dark resonances and Doppler heating. We apply this method to directly observe the micromotion modulated fluorescence spectra of both transitions and measure the dependence of the micromotion modulation index on the trap frequency. With a measurement time of 10 minutes, we can detect the center frequencies of both dipole transitions with a precision on the order of 200 kHz even in the presence of strong micromotion

Energy Transport in Trapped Ion Chains

We experimentally study energy transport in chains of trapped ions. We use a pulsed excitation scheme to rapidly add energy to the local motional mode of one of the ions in the chain. Subsequent energy readout allows us to determine how the excitation has propagated throughout the chain. We observe energy revivals that persist for many cycles. We study the behavior with an increasing number of ions of up to 37 in the chain, including a zig-zag configuration. The experimental results agree well with the theory of normal mode evolution. The described system provides an experimental toolbox for the study of thermodynamics of closed systems and energy transport in both classical and quantum regimes

Study of low energy Ytterbium atom-ion charge transfer collisions using a surface-electrode trap

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 113-114).We demonstrate a new isotope-selective system to measure low energy charge transfer collisions between ytterbium ions and atoms in the range of collisional energy from 2.2x 10-5 eV to 4.3x 10-3 eV, corresponding to effective temperature from 250 mK to 50 K. The charge transfer collisions are observed by spatially overlapping the 172yb+ ions in the surface-electrode trap and 174Yb atoms in the magneto-optical trap, and measuring ion loss. We confirm that, in the Langevin regime, the charge transfer collisional rate is independent of the collisional energy. The measured Langevin cross section is consistent with a theoretical value for the ytterbium atomic polarizability of 143 a.u., as calculated by Zhang and Dalgarno [1].by Thaned Pruttivarasin.S.B

Trapped ions in optical lattices for probing oscillator chain models

We show that a chain of trapped ions embedded in microtraps generated by an optical lattice can be used to study oscillator models related to dry friction and energy transport. Numerical calculations with realistic experimental parameters demonstrate that both static and dynamic properties of the ion chain change significantly as the optical lattice power is varied. Finally, we lay out an experimental scheme to use the spin degree of freedom to probe the phase space structure and quantum critical behavior of the ion chain

Spectroscopy, fundamental symmetry tests and quantum simulation with trapped ions

This dissertation reports on precision measurements of the atomic structure of calcium ions (40Ca+), application of trapped 40Ca+ ions as a probe for a violation of fundamental symmetry and prospects of performing quantum simulations with trapped ion.We demonstrate a novel technique to perform spectroscopy on the dipole transition of 40Ca+ that circumvents usual difficulties from dark resonances and Doppler heating. The center of the atomic transition can be detected to a precision of 200 kHz or less with an integration time of 10 minutes. We apply this method to directly measure the influence of micromotion on the fluorescence spectra and confirm the dependence of the modulation index on the radial trap frequency. We measure the branching fraction of the excited 2P1/2 state of 40Ca+ to be 0.93565(7) using a simple experimental scheme readily applicable to many other ion species. Our result for 40Ca+ distinguishes well among various theoretically calculated values, which is important in guiding further developments of the theoretical work.We apply the Ramsey spectroscopy technique based on a pair of correlated ions to probe the effect of the violation of local Lorentz invariance (LLI). The energy difference between the two components of the Bell state |PsiB> = |mJ=5/2,mJ=-5/2>+|mJ=1/2,mJ=-1/2> in the D5/2 manifold of 40Ca+ is monitored for 12 hours. We found that the energy component related to the violation of LLI varies less than 17±22 mHz. Assuming a hydrogen-like model of 40Ca+, the measurement result provides us the bound of the LLI parameter C(2)0 to be 1.7±2.2x10-17.Based on numerical simulations, we show that the Aubry transition in the Frenkel-Kontorova model with trapped ion can be observed for practical experimental parameters such as the strength and wavelength of the optical lattice, which serves as an external perturbing periodic potential. Moreover, we also show that the normal mode structure of ion chain can change significantly as we vary the strength of the optical lattice

Spectroscopy, fundamental symmetry tests and quantum simulation with trapped ions

This dissertation reports on precision measurements of the atomic structure of calcium ions (40Ca+), application of trapped 40Ca+ ions as a probe for a violation of fundamental symmetry and prospects of performing quantum simulations with trapped ion.We demonstrate a novel technique to perform spectroscopy on the dipole transition of 40Ca+ that circumvents usual difficulties from dark resonances and Doppler heating. The center of the atomic transition can be detected to a precision of 200 kHz or less with an integration time of 10 minutes. We apply this method to directly measure the influence of micromotion on the fluorescence spectra and confirm the dependence of the modulation index on the radial trap frequency. We measure the branching fraction of the excited 2P1/2 state of 40Ca+ to be 0.93565(7) using a simple experimental scheme readily applicable to many other ion species. Our result for 40Ca+ distinguishes well among various theoretically calculated values, which is important in guiding further developments of the theoretical work.We apply the Ramsey spectroscopy technique based on a pair of correlated ions to probe the effect of the violation of local Lorentz invariance (LLI). The energy difference between the two components of the Bell state |PsiB> = |mJ=5/2,mJ=-5/2>+|mJ=1/2,mJ=-1/2> in the D5/2 manifold of 40Ca+ is monitored for 12 hours. We found that the energy component related to the violation of LLI varies less than 17±22 mHz. Assuming a hydrogen-like model of 40Ca+, the measurement result provides us the bound of the LLI parameter C(2)0 to be 1.7±2.2x10-17.Based on numerical simulations, we show that the Aubry transition in the Frenkel-Kontorova model with trapped ion can be observed for practical experimental parameters such as the strength and wavelength of the optical lattice, which serves as an external perturbing periodic potential. Moreover, we also show that the normal mode structure of ion chain can change significantly as we vary the strength of the optical lattice