Electronic detection of collective modes of an ultracold plasma

Using a new technique to directly detect current induced on a nearby electrode, we measure plasma oscillations in ultracold plasmas, which are influenced by the inhomogeneous and time-varying density and changing neutrality. Electronic detection avoids heating and evaporation dynamics associated with previous measurements and allows us to test the importance of the plasma neutrality. We apply dc and pulsed electric fields to control the electron loss rate and find that the charge imbalance of the plasma has a significant effect on the resonant frequency, in excellent agreement with recent predictions suggesting coupling to an edge mode.     

Possible antihydrogen production using trapped plasmas

Since antiprotons have been captured in an ion trap, we consider the possibility of producing antihydrogen by merging cold trapped plasmas of antiprotons and positrons. The calculated, instantaneous rate for antihydrogen production by the 3-body recombination is much higher than for other proposed techniques, opening up intriguing experimental possibilities.     

Fast quantum gates for neutral atoms

We propose several schemes for implementing a fast two-qubit quantum gate for neutral atoms with the gate operation time much faster than the time scales associated with the external motion of the atoms in the trapping potential. In our example, the large interaction energy required to perform fast gate operations is provided by the dipole-dipole interaction of atoms excited to low-lying Rydberg states in constant electric fields. A detailed analysis of imperfections of the gate operation is given.     

g-Factor measurements of fission isomers

The current status of g-factor measurements of fission isomers is reviewed. In particular, we concentrate on magnetic and electric extranuclear perturbations affecting the fission isomers in solid environments. Recent results for isomers in²³⁷Pu and²³⁹Am are summarized and the single particle nature of these states is discussed.This work was supported in part by the National Science Foundation.     

193Ir Mössbauer study of bimetallic platinum-iridium catalysts

Using the 73.0 keV Mössbauer resonance in¹⁹³Ir, the chemical form of iridium in bimetallic Pt?Ir catalysts supported on amorphous silica has been determined after ionic co-exchange, calcination and reduction in hydrogen. The compositions of the highly dispersed bimetallic Pt_1?xIr_x clusters as determined from the measured isomer shifts reveal a strong tendency for segregation of iridium and platinum.     

Observation of reduced three-body recombination in a correlated 1D degenerate Bose gas

We investigate the correlation properties of a one-dimensional interacting Bose gas by loading a magnetically trapped 87Rb Bose-Einstein condensate (BEC) into a deep two-dimensional optical lattice. We measure the three-body recombination rate for both the BEC in the magnetic trap and the BEC loaded into the optical lattice. The recombination rate coefficient is a factor of 7 smaller in the lattice, which we interpret as a reduction in the local three-body correlation function in the 1D case. This is a signature of correlation intermediate between that of the uncorrelated, phase coherent, 1D, mean-field regime and the strongly correlated Tonks-Girardeau regime.