Imaging the Mott Insulator Shells using Atomic Clock Shifts

Microwave spectroscopy was used to probe the superfluid-Mott Insulator transition of a Bose-Einstein condensate in a 3D optical lattice. Using density dependent transition frequency shifts we were able to spectroscopically distinguish sites with different occupation numbers, and to directly image sites with occupation number n=1 to n=5 revealing the shell structure of the Mott Insulator phase. We use this spectroscopy to determine the onsite interaction and lifetime for individual shells

Berry-Like Phases in Structured Atoms and Molecules

Quantum mechanical phases arising from a periodically varying Hamiltonian are considered. These phases are derived from the eigenvalues of a stationary, “dressed” Hamiltonian that is able to treat internal atomic or molecular structure in addition to the time variation. In the limit of an adiabatic time variation, the usual Berry phase is recovered. For more rapid variation, nonadiabatic corrections to the Berry phase are recovered in perturbation theory, and their explicit dependence on internal structure emerges. Simple demonstrations of this formalism are given, to particles containing interacting spins, and to molecules in electric fields

Near-Infrared LIF Spectroscopy of HfF

The molecular ion HfF⁺ is the chosen species for a JILA experiment to measure the electron electric dipole moment (eEDM). Detailed knowledge of the spectrum of HfF is crucial to prepare HfF⁺ in a state suitable for performing an eEDM measurement [1]. We investigated the near-infrared electronic spectrum of HfF using laser-induced fluorescence (LIF) of a supersonic molecular beam. We discovered eight unreported bands, and assign each of them unambiguously, four to vibrational bands belonging to the transition [13.8]0.5 &larr; X1.5, and four to vibrational bands belonging to the transition [14.2]1.5 &larr; X1.5. Additionally, we report an improved measurement of vibrational spacing of the ground state, as well as anharmonicity &omega;ₑxₑ.</p

High-Resolution Spectroscopy on Trapped Molecular Ions in Rotating Electric Fields: A New Approach for Measuring the Electron Electric Dipole Moment

High-resolution molecular spectroscopy is a sensitive probe for violations of fundamental symmetries. Symmetry violation searches often require, or are enhanced by, the application of an electric field to the system under investigation. This typically precludes the study of molecular ions due to their inherent acceleration under these conditions. Circumventing this problem would be of great benefit to the high-resolution molecular spectroscopy community since ions allow for simple trapping and long interrogation times, two desirable qualities for precision measurements. Our proposed solution is to apply an electric field that rotates at radio frequencies. We discuss considerations for experimental design as well as challenges in performing precision spectroscopic measurements in rapidly time-varying electric fields. Ongoing molecular spectroscopy work that could benefit from our approach is summarized. In particular, we detail how spectroscopy on a trapped diatomic molecular ion with a ground or metastable &sup3;&Delta;₁ level could prove to be a sensitive probe for a permanent electron electric dipole moment (eEDM).</p

Microtraps and waveguides for Bose-Einstein condensates

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2003.Includes bibliographical references (leaves 126-149).Gaseous Bose-Einstein condensates containing up to 3 x 10⁶ ²³Na atoms were loaded into magnetic microtraps and waveguides on a microfabricated "atom chip" using optical tweezers. Single-mode propagation was observed along the waveguide. Closer to the microfabricated surface, perturbations to the waveguide potential spatially modulated the condensate density. The condensate lifetime was >[or equal to] 20 s and independent of the atom-surface separation, for separations >[or equal to] 70 [mu]m. Condensates were coherently split by deforming an optical single-well potential into a double-well potential. The relative phase between the two resulting condensates was determined from the matter wave interference pattern formed upon releasing the atoms from the separated potential wells. Coherent phase evolution was observed for condensates held separated by 13 [mu]m for <[or equal to ] 5 ms and was controlled by applying AC Stark shifts to either condensate. This demonstrated a trapped-atom interferometer. Vortices and spin textures were imprinted in spinor condensates using topological phases. The order parameter of condensates held in a Ioffe-Pritchard magnetic trap was manipulated by adiabatically varying the magnetic bias field along the trap axis. Fully inverting the axial bias field imprinted vortices in F = 1 and F = 2 condensates with 2h and 4h of angular momentum per particle, respectively. Reducing the axial bias field to zero distributed the condensate population across its 2F + 1 spin states, each with a different phase winding, and created a spin texture.(cont.) Partially condensed atomic vapors were confined by a combination of gravitational and magnetic forces. They were adiabatically decompressed, by weakening the gravito-magnetic trap to a mean frequency of 1 Hz, then evaporatively reduced in size to 2500 atoms. This lowered the peak condensate density to 5 x 10¹⁰ atoms/cm³ and cooled the entire cloud in all three dimensions to a kinetic temperature of 450±80 pK.by Aaron E. Leanhardt.Ph.D