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1.
XIE Guo-Qiu WANG An-Min MA Xiao-San 《理论物理通讯》2006,46(7)
The entanglement evolution of multipartite quantum states under a spin environment is analyzed. Due to interaction, the extent to which the entanglement vanishes depends not only on the size of system and the structure of quantum states, but also on the exchange couplings with environment. The decoherence-free subspaces have been identified by using the linear entropy. 相似文献
2.
XIE Guo-Qiu WANG An-Min MA Xiao-San 《理论物理通讯》2006,46(1):73-76
The entanglement evolution of multipartite quantum states under a spin environment is analyzed. Due to interaction, the extent to which the entanglement vanishes depends not only on the size of system and the structure of quantum states, but also on the exchange couplings with environment. The decoherence-free subspaces have been identified by using the linear entropy. 相似文献
3.
A key element in the architecture of quantum information processing is a reliable physical interface between fields and qubits. Here, we study the population transfer and entanglement for a two-level atomic system interacting with entangled spin coherent states (ESCSs) considering one- and two-mode interactions. The results show that decrease in the spin number provides a periodic behavior of the entanglement exhibiting the sudden death and birth phenomena. For large values of spin, the atom–field system stabilizes at high value of entanglement during the time evolution exhibiting maximum correlations for both cases of one- and two-mode interactions. Finally, we find an interesting correlation between the entanglement and the population transfer during the time evolution. In particular, we show that the population may be used as an indicator of nonlocal correlations in the system under consideration. 相似文献
4.
Xiao San Ma 《Optics Communications》2008,281(22):5633-5638
We investigate the entanglement dynamics and decoherence of a multipartite system under an environment which can exhibit a quantum phase transition. Our result implies that the entanglement evolution depends not only on the size of the system and the quantum states of concern but also on the environment. In the sense of the linear entropy to measure decoherence induced by the environment, the decoherence-free subspaces have been identified for our model. 相似文献
5.
Sudden Death, Birth and Stable Entanglement in a Two-Qubit Heisenberg XY Spin Chain 总被引:1,自引:0,他引:1 下载免费PDF全文
Taking the decoherence effect due to population relaxation into account, we investigate the entanglement properties for two qubits in the Heisenberg XY interaction and subject to an external magnetic field. It is found that the phenomenon of entanglement sudden death (ESD) as well as sudden birth (ESB) appear during the evolution process for particular initial states. The influence of the external magnetic field and the spin environment on ESD and ESB are addressed in detail. It is shown that the concurrence, a measure of entanglement, can be controlled by tuning the parameters of the spin chain, such as the anisotropic parameter, external magnetic field, and the coupling strength with their environment. In particular, we find that a critical anisotropy constant exists, above which ESB vanishes while ESD appears. It is also notable that stable entanglement, which is independent of different initial states of the qubits, occurs even in the presence of decoherence. 相似文献
6.
Z. Sun X. G. Wang Y. B. Gao C. P. Sun 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(3):521-530
We study a dynamic process of disentanglement by considering the
time evolution of bound entanglement for a quantum open system, two
qutrits coupling to a common environment. Here, the initial quantum
correlations of the two qutrits are characterized by the bound
entanglement. Both bosonic and spin environments are considered. We
found that the bound entanglement displays collapses and revivals,
and it can be stable against small temperature and time change. The
thermal fluctuation effects on bound entanglement are also
considered. 相似文献
7.
We investigate the entanglement dynamics of a two-spin-qubit system coupled to a spin environment with nonuniform coupling through using the time-dependent density-matrix renormalization group method. We show that the entanglement generation and decay depend on the number of environment spins, the coupling strength between the central spin system and the environment, and the initial state of the central spin system. 相似文献
8.
We study the dynamics evolution of a two-qubit Heisenberg XXX spin chain under a time-dependent rotating magnetic field. Based on the
algebraic structure of the non-autonomous system, the exact solution of the Schrödinger equation is obtained by using the method of algebraic dynamics. Based on the time-dependent analytical solution, we further study the entanglement evolution between the two coupled spins for different initial states, and find that the entanglement is determined by the coefficients of the initial state and the coupling constant $J$ of the system. 相似文献
9.
我们研究了含时旋转磁场中海森堡XXX模型下的双量子比特的动力学演化情况.基于此非自治系统的代数结构,我们用代数动力学方法求得了系统的精确解析解.在此基础上,进一步研究了在不同初态下系统的纠缠测度随时间的演化,发现纠缠测度由系统的初态的系数和耦合强度决定. 相似文献
10.
J. L. Guo Y. J. Mi H. S. Song 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2012,66(1):24
We study the dynamics of quantum discord of two-qubit system in a quantum spin
environment at finite temperature in the thermodynamics limit. Special attention is paid
to the difference between the entanglement and quantum discord when considering the
influences of the environment temperature and the initial system states. We show that in
the same range of the physical parameters, when the system states behave no entanglement
or entanglement sudden death, the quantum discord keeps nonzero. So the quantum discord is
more robust than entanglement under this decoherence environment. Furthermore, we also
illustrate that we can tune the parameters related to the system and the environment to
suppress the decay of quantum discord. 相似文献
11.
The time evolution of entanglement and coherence of two-qutrit states under an XY quantum environment which can exhibit a quantum phase transition has been analyzed. From our results, we find that the quantum phase transition can enhance the entanglement decay and coherence loss when the system is weakly coupled to the environment. Furthermore, the effect of the anisotropy parameter and the size of the environment on entanglement dynamics and coherence has also been discussed. 相似文献
12.
Kai-Le Sun Jun Chen Fa-Qiang Wang Ya-Fei Yu Zhi-Ming Zhang 《International Journal of Theoretical Physics》2016,55(2):730-742
We study the effects of the initial correlations in environment on the entanglement dynamics of spin system. The correlated environment is novelly simulated by two correlated wheel-shaped spin baths, each consisting of an intermediate spin interacting with a spin-ring. The correlations in environment are achieved by the entanglement between two intermediate spins. The spin system includes two system-spins, and the interaction between the spin system and the environment is implemented by the coupling between the system-spin and the intermediate spin. Firstly, we analyze the influences of the initial entanglement between the two intermediate spins, the coupling parameters and the temperature of the baths on the entanglement dynamics of the two system-spins in equivalent subsystems. It is demonstrated that the initial entanglement between the baths can act as a resource for the generation and the revivals of the entanglement of the system-spins. Moreover, the amount of the generation and the revivals of the entanglement of the system-spins can be enhanced by regulating the coupling constants and the temperature of the baths. In addition, we also investigate the influences of different coupling ratios in non-equivalent subsystems, it is found that changing the coupling ratios of two subsystems has a significant effect on the generation and revivals of entanglement of system-spins. 相似文献
13.
A. Fubini T. Roscilde V. Tognetti M. Tusa P. Verrucchi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,38(3):563-570
We consider a quantum many-body system made of N interacting
S=1/2 spins on a lattice, and develop a formalism which allows to
extract, out of conventional magnetic observables, the quantum
probabilities for any selected spin pair to be in maximally entangled
or factorized two-spin states. This result is used in order to
capture the meaning of entanglement properties in terms of magnetic
behavior. In particular, we consider the concurrence between two
spins and show how its expression extracts information on the presence
of bipartite entanglement out of the probability distributions
relative to specific sets of two-spin quantum states. We apply the
above findings to the antiferromagnetic Heisenberg model in a uniform
magnetic field, both on a chain and on a two-leg ladder. Using Quantum
Monte Carlo simulations, we obtain the above probability distributions
and the associated entanglement, discussing their evolution under
application of the field. 相似文献
14.
We investigate the entanglement dynamics and decoherence of a two-qubit system under a quantum spin environment at finite temperature in the thermodynamics limit. For the case under study, we find different initial states will result in different entanglement evolution, what deserves mentioning here is that the state |Ψ=cosα|01+sinα|10 is most robust than other states when π/2<α<π, since the entanglement remains unchanged or increased under the spin environment. In addition, we also find the anisotropy parameter Δ can suppress the destruction of decoherence induced by the environment, and the undesirable entanglement sudden death arising from the process of entanglement evolution can be efficiently controlled by the inhomogeneous magnetic field ζ. 相似文献
15.
Jing Nie Xiuyi Yang Qing-Xu Yu Chong Li 《International Journal of Theoretical Physics》2014,53(4):1159-1167
We theoretically study the entanglement dynamics of two coupled spins in a spin star environment, whose elements are coupled to local bosonic baths. It is shown that the dynamics of the entanglement depends on the initial state of the system and the coupling strength between the two coupled central spins, the interactions between the central system and the environment, as well as interactions between the bath spin and the reservoir. We also investigate the effect of non-Markovian dynamics in contrast with the Markovian case. It is found that the non-Markovian dynamics has a significant effect on the disentanglement between the two central spins. 相似文献
16.
J. L. Guo H. S. Song 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,61(3):791-796
The entanglement dynamics of three-qubit states under an XY spin
chain at finite temperature with three-site interaction is
investigated. It is shown that the three-site interaction does not
affect the behavior of quantum phase transition (QPT) induced by the
external magnetic field and does not induce new critical regions in
the XY model. In addition, concerned with the effect of the
three-site interaction on the entanglement evolution, we find the
three-site interaction can not only enhance but also suppress the
decay of the entanglement between the three-qubit system, which
depends on the initial states of the system and the parameters
related with the environmental spin chain. 相似文献
17.
Jia Liu Guo-Qing Liu Xiao-Hong Du 《International Journal of Theoretical Physics》2012,51(5):1509-1517
The dynamics of genuine three-qubit entanglement in Ising spin model is investigated under the effect of impurities with different
sites. The analytic expression for the three-tangle measurement is obtained. Results show that the impurity parameters exert
great effect on the entanglement value. When the impurity on the boundary sit of the spin chain, the positive contribution
of the impurity coefficient on the exchange interaction is greater, the stay time in the greater entanglement is longer. When
the impurity sitting in the spin chain, the entanglement variation is periodic with the evolution time only at some given
impurity coefficient. The realization of efficient control of the entanglement by appropriate combinations of the tunable
parameters should be possible. 相似文献
18.
利用负性纠缠度(negativity)研究了两个三能级原子系统在费米环境中的纠缠演化问题-结果表明,两个三能级原子系统的纠缠演化不仅依赖于系统和环境的相互作用强度,而且还依赖于系统所处的具体量子态-通过例子发现,系统和环境相互作用强度越大,纠缠衰减越快;对于纯态,仅当时间趋于无穷时纠缠才被完全破坏;对于混态,则在有限的时间内纠缠即被彻底破坏-通过一般的分析找到了一类免退相干的量子子空间-在这些子空间中,量子态不受环境的影响,故其纠缠不变-研究有助于理解费米环境造成的退相干对玻色系统纠缠的影响-
关键词:
费米环境
纠缠演化
两个三能级原子 相似文献
19.
The spin ladder with Dzyaloshinsky-Moriya interaction is investigated by using the quantum renormalization-group method. The entanglement and fidelity are periodic functions of the time and oscillate between zero and one. The oscillation period decreases with either the interaction in the spin ladder or the
Dzyaloshinsky-Moriya interaction increasing. When the system relates to the environment, both entanglement and fidelity oscillate with a damping rate related to intrinsic decoherence rate, the interaction in the spin ladder, and the Dzyaloshinsky-Moriya interaction. 相似文献
20.
X. S. Ma H. S. Cong J. Y. Zhang A. M. Wang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,48(2):285-292
The entanglement dynamics of three-qubit states under a general XY
spin-chain environment which can exhibit a quantum phase transition
is investigated by using negativity as entanglement measure. Our
results imply that the entanglement evolution depends not only on
the states of concern but also on the system-environment coupling,
the anisotropy parameter, the size of the environment, and the
strength of the external field applied to the environment. For the cases
under study, we find that the entanglement decay
is enhanced by quantum phase transition under weak coupling. The
conditions to identify quantum decoherence-free subspaces have been
discussed. 相似文献