Quantum control of the motional states of trapped ions through fast switching of trapping potentials

We propose a new scheme for supplying voltages to the electrodes of microfabricated ion traps, enabling access to a regime in which changes to the trapping potential are made on timescales much shorter than the period of the secular oscillation frequencies of the trapped ions. This opens up possibilities for speeding up the transport of ions in segmented ion traps and also provides access to control of multiple ions in a string faster than the Coulomb interaction between them. We perform a theoretical study of ion transport using these methods in a surface-electrode trap, characterizing the precision required for a number of important control parameters. We also consider the possibilities and limitations for generating motional state squeezing using these techniques, which could be used as a basis for investigations of Gaussian-state entanglement.Comment: Accepted by New Journal of Physic

Infrared Observations of AGN

We present results from an imaging and spectroscopic study of the dust properties of Seyfert galaxies in the 1-10um range. The data are compared to state of the art models of torus emission to constrain geometrical and physical properties of the obscuring medium.Comment: 2 pages, to appear in the IAU Symp.No.222 proceedings:"The Interplay among Black Holes, Stars and ISM in Galactic Nuclei", Gramado, Brazil, March 1-5, 200

Hyperonic crystallization in hadronic matter

Published in Hadrons, Nuclei and Applications, World Scientific, Singapore, Proc.of the Conference Bologna2000. Structure of the Nucleus at the Dawn of the Century, G. Bonsignori, M. Bruno, A. Ventura, D. Vretenar Editors, pag. 319.Comment: 4 pages, 2figure

Journal Staff

Electrical properties and strain gauge factor of Cr/SiOx cermet films with compositions 50/50 and 70/30 wt% were investigated in order to evaluate their use in strain gauge devices. The films were deposited by flash evaporation. The microstructures and resulting phases were characterized by electron diffraction and electron microscopy. The influence of the thickness and deposition rate on the sheet resistance, the temperature coefficient of resistance and the gauge factor were investigated. The results are consistent with a mixed conduction mechanism with metallic and a thermally activated tunneling components, between interconnected and discrete conductive phases, respectively.Se investigaron las propiedades eléctricas y el factor extensométrico de películas del cermet- Cr/SiOx en composiciones 50/50 y 70/30 % en peso, para evaluar su uso en dispositivos "strain gauge". Las películas fueron depositadas por evaporación "flash". Las estructuras y fases resultantes fueron caracterizadas por microscopía y difracción de electrones. Se estudió la influencia del espesor y la velocidad del depósito sobre la resistencia laminar, el coeficiente térmico de resistencia y el factor extensométrico. Los resultados son consistentes con un mecanismo de conducción mixto, con una componente metálica y otra por efecto túnel térmicamente activado, entre fases conductoras interconectadas y discretas, respectivamente

Multi-wavelength Observations of the Giant X-ray Flare Galaxy NGC 5905: signatures of tidal disruption

NGC 5905 is one of the few galaxies with no prior evidence for an AGN in which an X-ray flare, due to the tidal disruption of a star by the massive black hole in the center of the galaxy, was detected by the RASS in 1990-91. Here we present analysis of late-time follow-up observations of NGC 5905 using Chandra, Spitzer VLA 3 GHz and 8 GHz archival data and GMRT 1.28 GHz radio observations. The X-ray image shows no compact source that could be associated with an AGN. Instead, the emission is extended -- likely due to nuclear star formation and the total measured X-ray luminosity is comparable to the X-ray luminosity determined from the 2002 Chandra observations. Diffuse X-ray emission was detected close to the circum-nuclear star forming ring. The Spitzer 2006 mid-infrared spectrum also shows strong evidence of nuclear star formation but no clear AGN signatures. The semi-analytical models of Tommasin et. al. 2010 together with the measured [OIV]/[NeII] line ratio suggest that at most only 5.6% of the total IR Flux at 19 $\mu$m is being contributed by the AGN. The GMRT 1.28 GHz observations reveal a nuclear source. In the much higher resolution VLA 3 GHz map, the emission has a double lobed structure of size 2.7'' due to the circumnuclear star forming ring. The GMRT 1.28 GHz peak emission coincides with the center of the circumnuclear ring. We did not detect any emission in the VLA 8 GHz (1996) archival data. The 3 $\sigma$ upper limits for the radio afterglow of the TDE at 1.28 GHz, 3 GHz and 8 GHz are 0.17 mJy, 0.09 mJy and 0.09 mJy, respectively. Our studies thus show that (i) NGC 5905 has a declining X-ray flux consistent with a TDE, (ii) the IR flux is dominated by nuclear star formation, (iii) the nuclear radio emission observed from the galaxy is due to circumnuclear star formation, (iv) no compact radio emission associated with a radio afterglow from the TDE is detected.Comment: 12 pages, 8 figures, accepted to be published in Astrophysics and Space Scienc

On the semiclassical mass of S2{\mathbb S}^2-kinks

One-loop mass shifts to the classical masses of stable kinks arising in a massive non-linear ${\mathbb S}^2$-sigma model are computed. Ultraviolet divergences are controlled using the heat kernel/zeta function regularization method. A comparison between the results achieved from exact and high-temperature asymptotic heat traces is analyzed in depth.Comment: RevTex file, 15 pages, 2 figures. Version to appear in Journal of Physics

Quicksort with unreliable comparisons: a probabilistic analysis

We provide a probabilistic analysis of the output of Quicksort when comparisons can err.Comment: 29 pages, 3 figure