71,521 research outputs found
Photoproduction of and in the reaction \gamma \lowercase{p} \to K^+ \Lambda \pi^0 at Jefferson Lab
The search for missing nucleon resonances using coupled channel analysis has
mostly been concentrated on and channels, while the contributions
of and channels have not been investigated thoroughly mostly due
to the lack of data. With an integrated luminosity of about 75 , 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 has
been investigated. Preliminary results of the and
cross sections are not negligible compared with the
channels. The invariant mass spectrum is dominated by the
signal and no significant structure was found around the
region.Comment: 4 pages, 3 figures, to be publised on the NSTAR05 proceeding
Optimal transfer of an unknown state via a bipartite operation
A fundamental task in quantum information science is to transfer an unknown
state from particle to particle (often in remote space locations) by
using a bipartite quantum operation . We suggest the power of
for quantum state transfer (QST) to be the maximal average
probability of QST over the initial states of particle and the
identifications of the state vectors between and . We find the QST power
of a bipartite quantum operations satisfies four desired properties between two
-dimensional Hilbert spaces. When and 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
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
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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