44,829 research outputs found
Wave packet transmission of Bloch electron manipulated by magnetic field
We study the phenomenon of wave packet revivals of Bloch electrons and
explore how to control them by a magnetic field for quantum information
transfer. It is showed that the single electron system can be modulated into a
linear dispersion regime by the "quantized" flux and then an electronic wave
packet with the components localized in this regime can be transferred without
spreading. This feature can be utilized to perform the high-fidelity transfer
of quantum information encoded in the polarization of the spin. Beyond the
linear approximation, the re-localization and self-interference occur as the
novel phenomena of quantum coherence.Comment: 6 pages, 5 figures, new content adde
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
Dimerization-assisted energy transport in light-harvesting complexes
We study the role of the dimer structure of light-harvesting complex II (LH2)
in excitation transfer from the LH2 (without a reaction center (RC)) to the LH1
(surrounding the RC), or from the LH2 to another LH2. The excited and
un-excited states of a bacteriochlorophyll (BChl) are modeled by a quasi-spin.
In the framework of quantum open system theory, we represent the excitation
transfer as the total leakage of the LH2 system and then calculate the transfer
efficiency and average transfer time. For different initial states with various
quantum superposition properties, we study how the dimerization of the B850
BChl ring can enhance the transfer efficiency and shorten the average transfer
time.Comment: 11 pages, 6 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
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