共查询到20条相似文献,搜索用时 31 毫秒
1.
研究了两个初始处于纠缠相干态上的宏观场各自独立地与一个环境相互作用的系统, 环境对腔场的影响只体现在腔场光子数的泄漏上. 采用共生纠缠(concurrence)度量两个宏观场间的纠缠, 并给出宏观场纠缠的解析解, 以分析这种系统中宏观场纠缠的动力学特性. 研究表明当场的初始平均光子数较大时, 即使很小的光子泄漏率也会导致腔场间出现纠缠突然死亡现象. 同时研究结果也表明光子从腔场泄漏到环境后会导致两环境间的纠缠突然产生, 而这种纠缠产生的时机直接与腔场的初始光子数相关. 本文还进一步发现在大光子数的情况下, 在任何时刻任意一个腔场与任意一个环境间都不会产生纠缠.
关键词:
纠缠相干态
环境
纠缠突然死亡
纠缠突然产生 相似文献
2.
We study the nonlocal correlations and quantum entanglement for two deformed bosonic fields of arbitrary deformation parameters, q 1 and q 2, prepared in an entanglement of deformed coherent states. As a measure of entanglement, we use the von Neumann entropy and investigate its behavior for different strength regimes of the optical fields. We find that the photon number can enhance the von Neumann entropy, and the deformation parameters can restrain the system entanglement. 相似文献
3.
We consider entanglement dynamics of double intensity-dependent coupling Jaynes-Cummings models with two different initial
light fields, which one is in the squeezed vacuum state and another is in the coherent state. The results show that, when
the compressibility factor and the mean photon number are smaller, the concurrence of atoms exhibits phenomenon of dead and
revival periodically, and the entanglement perfectly transferres between the atoms and the fields. As the value of them grow
larger, the entanglement sudden death and sudden revival come out. Comparing with the normal double Jaynes-Cummings model,
we notice that the concurrence of the atoms which in the normal double Jaynes-Cummings models evolves irregularly. And it
is find that periodical entanglement pulse can be generated by using double intensity-dependent coupling Jaynes-Cummings models.
This result might be useful in quantum information processes. 相似文献
4.
In this paper, we study a Hamiltonian system constituted by two coupled two-level atoms (qubits) interacting with a nonlinear generalized cavity field. The nonclassical two-qubit correlation dynamics are investigated using Bures distance entanglement and local quantum Fisher information under the influences of intrinsic decoherence and qubit–qubit interaction. The effects of the superposition of two identical generalized coherent states and the initial coherent field intensity on the generated two-qubit correlations are investigated. Entanglement of sudden death and sudden birth of the Bures distance entanglement as well as the sudden changes in local Fisher information are observed. We show that the robustness, against decoherence, of the generated two-qubit correlations can be controlled by qubit–qubit coupling and the initial coherent cavity states. 相似文献
5.
Qi-Liang He 《Optics Communications》2011,284(6):1714-1718
We investigate the entanglement dynamics and the phenomenon of entanglement sudden death in the two-photon Tavis-Cummings model with an added nonlinear kerr-like medium. It is shown that the phenomenon of entanglement sudden death can be controlled by the nonlinear kerr-like medium. Furthermore, the influence of dipole-dipole interaction on entanglement between atoms is also discussed. It is found that the phenomenon of entanglement sudden death can be weakened by the dipole-dipole interaction. Finally, we investigate the influence of kerr medium and dipole-dipole interaction on the three-partite entanglement of the system by making use of the state preparation fidelity. 相似文献
6.
7.
We have experimentally demonstrated how two beams of light separated by an octave in frequency can become entangled after their interaction in a chi;{(2)} nonlinear medium. The entangler was a nonlinear optical resonator that was strongly driven by coherent light at the fundamental and second-harmonic wavelengths. An interconversion between the fields created quantum correlations in the amplitude and phase quadratures, which were measured by two independent homodyne detectors. Analysis of the resulting correlation matrix revealed a wave function inseparability of 0.74(1)<1, thereby satisfying the criterion of entanglement. 相似文献
8.
The entanglement dynamics of system, where atoms A and B interact with single mode cavity fields a and b respectively, is studied. The interaction between atom A and cavity a may be described by using the typical Jaynes Cummings model, while that between the atom B and cavity b filled with a Kerr medium is of a two-photon process. For a certain initial atom entanglement state, there is an entanglement sudden death effect between the two atoms. The Kerr medium in the cavity b can effectively prevent the undesirable entanglement sudden death from occurring. Also, from the viewpoint of the population dynamics, we discuss why the Kerr medium can do so. 相似文献
9.
10.
Jian-Song Zhang Fen Liu Ai-Xi Chen 《International Journal of Theoretical Physics》2016,55(9):4016-4026
We investigate the effects of classical driving fields on the dynamics of purity, spin squeezing, and genuine multipartite entanglement (based on the Peres-Horodecki criterion ) of three two-level atoms within three separated cavities prepared in coherent states in the presence of decoherence. The three qubits are initially entangled and driven by classical fields. We obtain an analytical solution of the present system using the superoperator method. We find that the genuine multipartite entanglement measured by an entanglement monotone based on the Peres-Horodecki criterion can stay zero for a finite time and revive partially later. This phenomenon is similar to the sudden death of entanglement of two qubits and can be controlled efficiently by the classical driving fields. The amount of purity, spin squeezing, and genuine multipartite entanglement decrease with the increase of mean photon number of cavity fields. Particularly, the purity and genuine multipartite entanglement could be simultaneously improved by the classical driving fields. In addition, there is steady state genuine multipartite entanglement which can also be adjusted by the classical driving fields. 相似文献
11.
By introducing the nonlinear effects that arise from Kerr medium, we theoretically study the nonlinear effect and the entanglement
between two atoms in two coupled cavities. We give out the process of dynamic stability and solve the eigen problem of the
system under high-intensive fields. The dynamics of the two coupled cavity with high-intensity fields inside is also studied
numerically, the effects of atom-field coupling on the self-trapping as well as on the entanglement are also analyzed and
discussed. In vacuum and high-intensity fields we calculate the concurrence of the two atoms in both theoretical and realistic
situation, and discuss the nonlinear effect on the atomic entanglement. The result shows that the nonlinear interaction can
play a controlling role in entangling two atoms. 相似文献
12.
Entanglement dynamics of the atoms in the double Jaynes-Cummings models with the Kerr medium is studied, and the effect of the Kerr medium on that is examined. The result shows that, the Kerr medium can control the entanglement dynamics of the atoms and repress entanglement sudden death. We can obtain the maximum entanglement between the atoms by strengthening the nonlinear interaction of the Kerr medium. 相似文献
13.
ZHANG Jin-Hua LIANG Mai-Lin YUAN Bing ZHANG Fu-Lin 《理论物理通讯》2008,49(1):83-87
For nonlinear interactions with different forms of intensity-dependent coupling, entanglement transfer from the correlated two-mode SU(1,1) coherent states (SCS) to the initially separable and mixed atoms is investigated. It is found that suitable intensity-dependent coupling can enhance the entanglement transfer and make the atomic entanglement evolve periodically especially for the initially mixed atomic states. For SCS, the entanglement between the two modes is strengthened with the increase of the photon number difference (PND) between the two modes of the fields. When PND is odd, the entanglement between the atoms is less than that when PND is even. 相似文献
14.
克尔介质中纠缠光与三能级原子作用的光子统计 总被引:8,自引:2,他引:6
采用求解薛定谔方程和数值计算方法,研究了克尔介质中双模纠缠相干光场与三能级原子相互作用系统的光子统计性质,分析了双模纠缠相干光场的纠缠程度、克尔介质与光场的耦合强度、双模光的平均光子数和原子基态概率幅对光子统计性质的影响。结果表明:双模纠缠相干光场的纠缠程度对光子统计性质没有明显的影响;克尔效应增强使光子统计性质的时闻演化曲线的振荡频率变大、振荡幅度变小;当保持场模1的平均光子数不变而场模2的平均光子数变小时,光子统计性质的时间演化曲线的振荡幅度变大。 相似文献
15.
Jun-Mao Ma Zhi-Yong Jiao Ning Li 《International Journal of Theoretical Physics》2007,46(10):2550-2559
The properties of quantum entanglement in the two-photon Tavis–Cummings model with a Kerr nonlinearity are studied in terms
of quantum information entropy theory. The reduced quantum entropy is employed to investigate the quantum entanglement between
two two-level atoms and a single-mode coherent field. The relative quantum entropy is employed to investigate the quantum
entanglement between the two two-level atoms. The influences of the nonlinear interaction of the Kerr medium with the field
and the atomic dipole-dipole interaction on the properties of quantum entanglement of the system are also examined. Some important
results are obtained. 相似文献
16.
Quantum entanglement in the system of a moving V-type three-level atom interacting with the SU(1,1)-related coherent fields
下载免费PDF全文
![点击此处可从《中国物理》网站下载免费的PDF全文](/ch/ext_images/free.gif)
In a system with a moving V-type three-level atom interacting with
the SU(1,1)-related coherent fields,
we investigate the entanglement between the moving three-level atom
and the SU(1,1)-related coherent fields by
using the quantum-reduced entropy, and that
between the SU(1,1)-related
coherent fields by using the quantum relative
entropy of entanglement. It is shown that the two kinds of entanglement
are dependent on the atomic motion and
exhibit the periodic evolution with a
period of 2π/p. The maximal atom--field qutrit entanglement
state can be prepared, and the entanglement preservation
of the SU(1,1)-related coherent fields
can be realized in the interacting process
via the appropriate selection of system
parameters and interaction time. 相似文献
17.
We investigate the entanglement dynamics via the concurrence of two distant atoms interacting off-resonantly with two cavity fields in Fock states,respectively.We find that the evolution of entanglement has sudden death and sudden birth phenomena,that with the increase of photon numbers in the two cavities,the alternate frequency of sudden death and sudden birth turns fast,and that the amplitude of concurrence oscillates regularly with oscillation frequency becoming slow when the cavity fields have the same photon numbers.While,the maximum of concurrence declines and the amplitude of concurrence oscillates irregularly when the two cavity fields have different photon numbers.In addition,we find the length of death time is dependent on the initial entanglement. 相似文献
18.
Based on the quantum information theory, this paper has investigated
the entanglement properties of a system which is composed of the two
entangled two-level atoms interacting with the two-mode entangled
coherent fields. The influences of the strength of light field and
the two parameters of entanglement between the two-mode fields on
the field entropy and on the negative eigenvalues of partial
transposition of density matrix are discussed by using numerical
calculations. The result shows that the entanglement properties in a
system of a pairwise entangled states can be controlled by
appropriately choosing the two parameters of entanglement between
the two-mode entangled coherent fields and the strength of two light
fields respectively. 相似文献
19.
运用全量子理论并结合数值计算方法,研究了克尔介质腔中处于贝尔态的两个全同二能级纠缠原子与双模纠缠相干光场相互作用系统的光子统计特性。讨论了双原子体系的初态、初始光场的平均光子数、双模纠缠相干光场的纠缠程度以及克尔介质与双模光场的耦合强度对光子统计特性的影响。结果表明:忽略克尔介质的作用时,只有当双原子体系的初态为0β1〉或1β1〉时,在一定的条件下才可出现光子的反聚束效应,而当双原子体系的初态为β00〉、1β0〉时,光场在其演化过程中不出现光子的反聚束效应。而当考虑克尔介质的作用时,四种初态下光场演化过程中均有可能出现光子的反聚束效应。光子的反聚束效应出现的次数、时间和深度极其敏感地依赖于初始光场的平均光子数和克尔介质与双模光场的耦合强度,同时也受到双模纠缠光场的纠缠程度的影响。 相似文献
20.
We study the interaction between a single-mode quantized field and a quantum system composed of two qubits. We suppose that two qubits initially be prepared in the mixed and separable state, and study how entanglement between two qubits arises in the course of evolution according to the Jaynes-Cummings type interaction with nonclassical radiation field. We also investigate the relation between entanglement and purity of qubit subsystem. We show that different photon statistics have different effects on the dynamical behavior of the qubit subsystem. When the qubits are initially prepared in the maximally mixed and separable state, for coherent state field we cannot find entanglement between two qubits; for squeezed state field entanglement between two qubits exists in several short period of time; for even and odd coherent state fields of large photon number, the dynamical behavior of the entanglement between two qubits shows collapse and revival phenomenon. For odd coherent state field of small photon number, the entanglement with both qubits initially prepared in maximally mixed state can be stronger than that with both qubits initially prepared in pure states. For fields of small photon number, the entanglement strongly depends on the states they are initially prepared in. For coherent state field, and odd and even coherent state fields of large photon number, the entanglement only depends on the purity of the initial state of qubit subsystem. We also show that during the evolution the unentangled state may be purer than the entangled state, and the maximum degree of entanglement may not occur at the time when the qubit subsystem is in the purist state. 相似文献