2,149 research outputs found
Diffusion and entanglement of a kicked particle in an infinite square well under frequent measurements
We investigate the dynamics of a kicked particle in an infinite square well
undergoing frequent measurements of energy. For a large class of periodic
kicking force, constant diffusion is found in such a non-KAM system. The
influence of phase shift of the kicking potential on the short-time dynamical
behavior is discussed. The general asymptotical measurement-assisted diffusion
rate is obtained. The entanglement between the particle and the measuring
apparatus is investigated. There exist two distinct dynamical behaviors of
entanglement. The bipartite entanglement grows with the kicking steps and it
gains larger value for the more chaotic system. However, the pairwise
entanglement between the system of interest and the partial spins of the
measuring apparatus decreases with the kicking steps. The relation between the
entanglement and quantum diffusion is also analyzed.
PACS numbers: 05.45.Mt, 03.65.TaComment: 7 pages, 5 figures, RevTex4, Accepted by Phys. Rev.
Stationary state entanglement and total correlation of two qubits or qutrits
We investigate the mutual information and entanglement of stationary state of
two locally driven qubits under the influence of collective dephasing. It is
shown that both the mutual information and the entanglement of two qubits in
the stationary state exhibit damped oscillation with the scaled action time
of the local external driving field. It means that we can control
both the entanglement and total correlation of the stationary state of two
qubits by adjusting the action time of the driving field. We also consider the
influence of collective dephasing on entanglement of two qutrits and obtain the
sufficient condition that the stationary state is entangled.Comment: 5 pages, 2 figures, RevTex
Nonclassicality of quantum excitation of classical coherent field in photon loss channel
We investigate the nonclassicality of photon-added coherent states in the
photon loss channel by exploring the entanglement potential and negative Wigner
distribution. The total negative probability defined by the absolute value of
the integral of the Wigner function over the negative distribution region
reduces with the increase of decay time. The total negative probability and the
entanglement potential of pure photon-added coherent states exhibit the similar
dependence on the beam intensity. The reduce of the total negative probability
is consistent with the behavior of entanglement potential for the dissipative
single-photon-added coherent state at short decay times.Comment: 5 pages, 5 figures, RevTex4, submitte
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