71,125 research outputs found

    Photoproduction of K∗+ΛK^{*+}\Lambda and K+Σ(1385)K^+\Sigma(1385) in the reaction \gamma \lowercase{p} \to K^+ \Lambda \pi^0 at Jefferson Lab

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    The search for missing nucleon resonances using coupled channel analysis has mostly been concentrated on NπN\pi and KYKY channels, while the contributions of K∗YK^*Y and KY∗KY^* channels have not been investigated thoroughly mostly due to the lack of data. With an integrated luminosity of about 75 pb−1pb^{-1}, the photoproduction data using a proton target recently collected by the CLAS Collaboration at Jefferson Lab with a photon energy range of 1.5-3.8 GeV provided large statistics for the study of light hyperon photoproduction through exclusive reactions. The reaction γp→K+Λπ0\gamma p \to K^+ \Lambda \pi^0 has been investigated. Preliminary results of the K∗+ΛK^{*+}\Lambda and K+Σ(1385)K^+\Sigma(1385) cross sections are not negligible compared with the KYKY channels. The Λπ0\Lambda \pi^0 invariant mass spectrum is dominated by the Σ(1385)\Sigma(1385) signal and no significant structure was found around the Σ(1480)\Sigma(1480) region.Comment: 4 pages, 3 figures, to be publised on the NSTAR05 proceeding

    Optimal transfer of an unknown state via a bipartite operation

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    A fundamental task in quantum information science is to transfer an unknown state from particle AA to particle BB (often in remote space locations) by using a bipartite quantum operation EAB\mathcal{E}^{AB}. We suggest the power of EAB\mathcal{E}^{AB} for quantum state transfer (QST) to be the maximal average probability of QST over the initial states of particle BB and the identifications of the state vectors between AA and BB. We find the QST power of a bipartite quantum operations satisfies four desired properties between two dd-dimensional Hilbert spaces. When AA and BB are qubits, the analytical expressions of the QST power is given. In particular, we obtain the exact results of the QST power for a general two-qubit unitary transformation.Comment: 6 pages, 1 figur

    Magnetically-induced reconstructions of the ground state in a few-electron Si quantum dot

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    We report unexpected fluctuations in the positions of Coulomb blockade peaks at high magnetic fields in a small Si quantum dot. The fluctuations have a distinctive saw-tooth pattern: as a function of magnetic field, linear shifts of peak positions are compensated by abrupt jumps in the opposite direction. The linear shifts have large slopes, suggesting formation of the ground state with a non-zero angular momentum. The value of the momentum is found to be well defined, despite the absence of the rotational symmetry in the dot.Comment: 5 pages, 4 figures, accepted to PR

    Double-dot charge transport in Si single electron/hole transistors

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    We studied transport through ultra-small Si quantum dot transistors fabricated from silicon-on-insulator wafers. At high temperatures, 4K<T<100K, the devices show single-electron or single-hole transport through the lithographically defined dot. At T<4K, current through the devices is characterized by multidot transport. From the analysis of the transport in samples with double-dot characteristics, we conclude that extra dots are formed inside the thermally grown gate oxide which surrounds the lithographically defined dot.Comment: 4 pages, 5 figures, to appear in Appl. Phys. Let
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