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71.
This paper proposes an alternative scheme for generating four-photon W state via cavity QED. The scheme bases on the resonant interaction of a A-type three level atom with two bimodal cavities. The detection of atom collapses the cavity to the desired state. Comparing with previous schemes, the advantage of this scheme is that the interaction time can be greatly shortened since it uses the resonant interaction between atom and cavities. Moreover, the proposed scheme is more experimentally feasible than the previous ones. 相似文献
72.
73.
Teleportation for an Ionic Entangled Internal State by Entanglement Swapping 总被引:4,自引:0,他引:4 下载免费PDF全文
We present an effective scheme to teleport an unknown ionic entangled internal state via trapped ions without joint Bell-state measurement. In the constructed quantum channel process, we adopt entanglement swapping to avoid decrease of entanglement during the distribution of particles. Thus our scheme provides new prospects for quantum teleportation over longer distance. The distinct advantages of our scheme are that our scheme is insensitive to heating of vibrational mode and can be generalized to teleport an N-ion electronic entangled GHZ class state. Furthermore, in our scheme the success probability can reach 1. 相似文献
74.
We propose a method to realize the teleportation of an unknown entangled state that consists of many qudits through a partially entangled-qudit quantum channel with the help of 2 log2 d-bit classical communication. The operations used in the teleportation process include a generalized Bell-state measurement and a series of singlequdit π-measurements performed by Alice, a series of generalized qudit-Pauli gates and two-level unitary gates, as well as a qubit measurement performed by Bob. For a maximally entangled quantum channel, the successful probability of the teleportation becomes unit. 相似文献
75.
We present a scheme for perfectly teleporting an arbitrary and unknown N-particle GHZ-class state from a sender to a receiver. We just need one quantum channel composed of two or three particles in the maximally entangled state. The sender performs one Bell-state measurement on two of her particles and N - 1 Hadamard operations and N - 1 yon Neumann measurements on the rest N - 1 particles. The receiver adopts one corresponding unitary transformation on his particles shared with the sender. After that, the receiver can obtain the original N-particle GHZ-class state by introducing N - 1 ancillary particles and carrying out N - 1 controlled-NOT operations. We also generalize the scheme to the case of controlled teleportation. 相似文献
76.
Based on the exact solution of the time-dependent Schr\"{o}dinger
equation for two-species Bose--Einstein condensates (BECs)
consisting of two hyperfine states of the atoms coupled by a tuned
adiabatic and time-varying Raman coupling, we obtain analytically
the entanglement dynamics of the system with various initial
states, particularly the SU(2) coherent state, for both of
cases with and without the nonlinear interactions. It is shown
that the effect of nonlinear interaction on the entanglement
appears only in a longer time period depending on the BEC
parameters. 相似文献
77.
In this paper, we derive an explicit analytic expression of the
relative entropy between two general Gaussian states. In the
restriction of the set for Gaussian states and with the help of
relative entropy formula and Peres--Simon separability criterion,
one can conveniently obtain the relative entropy entanglement for
Gaussian states. As an example, the relative entanglement for a
two-mode squeezed thermal state has been obtained. 相似文献
78.
We investigate the entanglement in a system of two coupling atoms
interacting with a single-mode field
by means of quantum information entropy theory.
The quantum entanglement between the two atoms and the coherent field is discussed by using
the quantum reduced entropy,
and the entanglement between the two coupling atoms is also investigated
by using the quantum relative entropy.
In addition, the influences of the atomic dipole--dipole interaction
intensity and
the average photon number of the coherent field on the degree of the entanglement is examined.
The results show that the evolution of the degree of entanglement between the two atoms
and the field is just opposite to that of the degree of entanglement between the two atoms.
And the properties of the quantum entanglement in the system rely on the
atomic dipole--dipole
interaction and the average photon number of the coherent field. 相似文献
79.
80.
用Von Neumann熵研究了附加克尔介质的压缩真空场与二能级原子依赖强度耦合相互作用量子体系的量子纠缠特性.讨论了初始压缩真空场的压缩度以及克尔非线性作用的强度对该量子体系纠缠特性的影响.结果表明,克尔介质的非线性作用的强弱可以改变体系量子纠缠的周期性;在初始压缩度较大(r=5)时,克尔介质的非线性作用可导致原子与场持续地处于最大纠缠态,无消纠缠态或持续地处于消纠缠态.
关键词:
压缩真空态
克尔介质
依赖强度耦合J-C模型
Von Neumann熵
量子纠缠 相似文献