73,376 research outputs found
Quantum state swapping via qubit network with Hubbard interaction
We study the quantum state transfer (QST) in a class of qubit network with
on-site interaction, which is described by the generalized Hubbard model with
engineered couplings. It is proved that the system of two electrons with
opposite spins in this quantum network of sites can be rigorously reduced
into one dimensional engineered single Bloch electron models with central
potential barrier. With this observation we find that such system can perform a
perfect QST, the quantum swapping between two distant electrons with opposite
spins. Numerical results show such QST and the resonant-tunnelling for the
optimal on-site interaction strengths.Comment: 4 pages, 3 figure
Generation of GHZ and W states for stationary qubits in spin network via resonance scattering
We propose a simple scheme to establish entanglement among stationary qubits
based on the mechanism of resonance scattering between them and a
single-spin-flip wave packet in designed spin network. It is found that through
the natural dynamical evolution of an incident single-spin-flip wave packet in
a spin network and the subsequent measurement of the output single-spin-flip
wave packet,multipartite entangled states among n stationary qubits,
Greenberger-Horne-Zeilinger (GHZ) and W states can be generated.Comment: 8 pages, 6 figure
Intrinsic Charm Flavor and Helicity Content in the Proton
Contributions to the quark flavor and spin observables from the intrinsic
charm in the proton are discussed in the SU(4) quark meson fluctuation model.
Our results suggest that the probability of finding the intrinsic charm in the
proton is less than 1%. The intrinsic charm helicity is small and negative,
. The fraction of the total quark helicity
carried by the intrinsic charm is less than 2%, and c_\up/c_\dw=35/67.Comment: 4 pages, 2 tables (revised version
The effects of disorder and interactions on the Anderson transition in doped Graphene
We undertake an exact numerical study of the effects of disorder on the
Anderson localization of electronic states in graphene. Analyzing the scaling
behaviors of inverse participation ratio and geometrically averaged density of
states, we find that Anderson metal-insulator transition can be introduced by
the presence of quenched random disorder. In contrast with the conventional
picture of localization, four mobility edges can be observed for the honeycomb
lattice with specific disorder strength and impurity concentration. Considering
the screening effects of interactions on disorder potentials, the experimental
findings of the scale enlarges of puddles can be explained by reviewing the
effects of both interactions and disorder.Comment: 7 pages, 7 figure
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