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1.
通过求解系统的Milburn方程,研究了两能级原子与双模SU(1,1)相干态光场发生相互作用系统中,原子与场的纠缠及双模SU(1,1)相干态场的模间纠缠随时间的演化问题,讨论了内禀退相干、双模光子数差等对纠缠度的影响.结果表明,存在内禀退相干时,随着时间的演化,场-原子纠缠逐渐减小到一个确定值,而模间纠缠逐渐增大到一个确定值,两者演化的最终值只取决于双模光子数差和平均光子数,而与内禀退相干因子无关.
关键词:
Milburn理论
SU(1
1)相干态
量子约化熵
量子相对熵 相似文献
2.
Electromagnetically induced transparency and quadripartite macroscopic entanglement generated in a ring cavity 下载免费PDF全文
We propose a feasible scheme to generate electromagnetically induced transparency(EIT) and quadripartite macroscopic entanglement in an optomechanical system with one fixed mirror and three movable perfectly reflecting mirrors.We explore the EIT phenomena in this optomechanical system.Results show the appearance of EIT dips in the output field.Moreover,we demonstrate how steady-state quadripartite entanglement can be generated via radiation pressure.We also quantify the bipartite entanglement in each field-mirror subsystem and in the mirror-mirror subsystem.Findings show that a high intensity of entanglement between two subsystems can be achieved. 相似文献
3.
Guo Hui Yang Xiang Yang Miao Jun Feng Zhang 《International Journal of Theoretical Physics》2010,49(4):766-776
We report possibility of generating entanglement and steady entanglement between two identical atoms in free space with a
very natural way when their spatial separation is on the order of wavelength or less. We show a dynamical creation of entanglement
and steady entanglement due to the radiative coupling with different separable initial atomic states and study the entanglement
properties about this atomic subsystem. Not only the creation of steady state entanglement is decided by the initial atomic
states, but also the magnitude of the entanglement and the steady state entanglement are found to be strongly dependent on
the initial states. We derive a master equation for the atomic subspace and solve it analytically to show how the spontaneous
emission from the two atoms system induces entanglement and steady entanglement, the crossing coupling terms in master equation
can enhance the entanglement value. 相似文献
4.
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
5.
岳建林 《原子与分子物理学报》2018,35(1):95-100
在压缩真空库中,研究了原子与场的相互作用下二比特体系的量子discord和量子纠缠的动力学行为.重点分析了原子的初始态系数和压缩真空库的压缩系数对量子纠缠和量子discord的影响.通过数值分析我们得到,随着原子的初始态系数和压缩真空库的压缩系数值的增加,量子纠缠和量子discord都会减小,但量子纠缠比量子discord减小的更快一些.最后研究了在原子的初始态系数和压缩真空库的压缩系数的值相同的情况下,量子discord比量子纠缠存在的时间更长些. 相似文献
6.
ZOU Jian CAI Jin-Fang SHAO Bin LI Qian-Shu 《理论物理通讯》2005,44(2):259-268
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
7.
8.
内禀退相干下薛定谔猫态光场与原子相互作用系统的场熵演化 总被引:2,自引:2,他引:0
通过求解系统的Milburn方程,研究了二能级原子与薛定谔猫态光场相互作用系统中的场熵演化特性.讨论了内禀退相干,光场强度,相干态间的相位角对场熵演化的影响.结果表明: 内禀退相干下,随着时间的演化,场熵振荡逐渐减弱,光场与原子的纠缠度逐渐趋于恒值.并且光场与原子的最大纠缠度值只取决光场强度和相干态间的相位角,与内禀退相干因子无关.光场强度较小时,奇相干态光场与原子的纠缠度最大;偶相干态光场与原子的纠缠度值为最小;Yurke-Stoler相干态光场与原子的纠缠度值介于两者之间. 当内禀退相干因子不变、光场强度较大时,分别处于Yurke-Stoler相干态、偶相干态和奇相干态的光场与原子的纠缠度值趋近于相同. 相似文献
9.
通过求解系统的Milburn方程,研究了二能级原子与薛定谔猫态光场相互作用系统中的场熵演化特性.讨论了内禀退相干,光场强度,相干态间的相位角对场熵演化的影响.结果表明: 内禀退相干下,随着时间的演化,场熵振荡逐渐减弱,光场与原子的纠缠度逐渐趋于恒值.并且光场与原子的最大纠缠度值只取决光场强度和相干态间的相位角,与内禀退相干因子无关.光场强度较小时,奇相干态光场与原子的纠缠度最大;偶相干态光场与原子的纠缠度值为最小;Yurke-Stoler相干态光场与原子的纠缠度值介于两者之间. 当内禀退相干因子不变、光场强度较大时,分别处于Yurke-Stoler相干态、偶相干态和奇相干态的光场与原子的纠缠度值趋近于相同. 相似文献
10.
P. A. Bouvrie A. P. Majtey A. R. Plastino P. Sánchez-Moreno J. S. Dehesa 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2012,66(1):15
We investigate the entanglement-related features of the eigenstates of two exactly soluble atomic models: a one-dimensional
three-electron Moshinsky model, and a three-dimensional two-electron Moshinsky system in an external uniform magnetic field.
We analytically compute the amount of entanglement exhibited by the wavefunctions corresponding to the ground, first and second
excited states of the three-electron model. We found that the amount of entanglement of the system tends to increase with
energy, and in the case of excited states we found a finite amount of entanglement in the limit of vanishing interaction.
We also analyze the entanglement properties of the ground and first few excited states of the two-electron Moshinsky model
in the presence of a magnetic field. The dependence of the eigenstates’ entanglement on the energy, as well as its behaviour
in the regime of vanishing interaction, are similar to those observed in the three-electron system. On the other hand, the
entanglement exhibits a monotonically decreasing behavior with the strength of the external magnetic field. For strong magnetic
fields the entanglement approaches a finite asymptotic value that depends on the interaction strength. For both systems studied
here we consider a perturbative approach in order to shed some light on the entanglement’s dependence on energy and also to
clarify the finite entanglement exhibited by excited states in the limit of weak interactions. As far as we know, this is
the first work that provides analytical and exact results for the entanglement properties of a three-electron model. 相似文献
11.
Considering intrinsic decoherence, the two-atom two-mode
Raman coupled model is investigated in this paper. Utilizing the
constants of motion in this model, we obtain the analytic expressions
of the density operator of the system for investigating the entanglement
of two atoms. The speed of entanglement decay increases with the
increasing of the coupling coefficient of one atom. The difference
between the oscillation periods when the initial state parameter of
atomic subsystem belongs to two intervals becomes smaller with the
increasing of the coupling coefficient of one atom. The increasing
of the initial photon number of the second field can hasten the
vanishing of entanglement of atomic subsystem. The robustness of
atomic entanglement against decoherence depends on the interval of
the initial state parameter of atomic subsystem. 相似文献
12.
E. K. Bashkirov 《International Journal of Theoretical Physics》2018,57(12):3761-3771
We studied the entanglement of a quantum system consisting of a Jaynes-Cummings atom, thermal lossless cavity and an isolated atom. The analytical expressions of the atom-atom negativity for separable and entangled initial atomic states were obtained. The influence of a detuning between the atomic transition frequency and the field frequency and direct dipole-dipole interaction on an atom-atom entanglement is examined. We showed that for a separable initial atomic states a detuning might cause high atom-atom entanglement in the presence of the dipole-dipole interaction. We also obtained that for an entangled initial atomic state a detuning causes a stabilization of an entanglement oscillations both for model with dipole-dipole interaction and model without such interaction. 相似文献
13.
Fu-li Li Zhang-qi Yin 《量子光学学报》2006,12(B08):75-75
Two atomic clusters, which have NA and Ns two-level atoms, respectively, are placed in a cavity but separated spatially. There is no direct interaction between the atoms. All the atoms interact with a single-mode of the cavity field. Quantum entanglement between the two atomic clusters is investigated for various initial states of the two atomic clusters and the field. When the cavity field is initially in a Fock state, we find that the time evolution of entanglement quasi-periodically oscillates regardless of the initial states of atoms. The oscillation period increases as the initial photon number increases. When all the atoms in both of the atomic clusters are initially in the excited state, we show that there is no entanglement between the atomic clusters with NA = NB = 1 regardless the initial state of the cavity field. However, when either NA or NB is larger than one, we find that the entanglement always exists even for a strong thermal field. In cases with different initial states of the atomic clusters, we notice that the entanglement becomes stronger as number of the atoms increases. When all the atoms in both of the clusters in the ground state, we also find that the entanglement can be enhanced even by a thermal field. We also notice that a single qubit can be entangled with multi-atoms which are initially in the ground state by the cavity field initially being in vacuum, thermal, coherent, and squeezed states. 相似文献
14.
Tarek M. El-Shahat Mohamad Kh. Ismail Abdullah F. Al Naim 《Journal of Russian Laser Research》2018,39(3):231-241
We investigate the damped interaction between two Λ-type three-level atoms and a quantized single-mode cavity field, for which the Hamiltonian of the field is rewritten in Caldirola–Kanai form. We obtain the wave functions for the case where the two atoms are initially prepared in arbitrary pure states and the field is initially prepared in the coherent state. We investigate numerically the influence of the damping parameter on the temporal behavior of the Mandel Q-parameter, linear entropy, and normal squeezing. We find the damping parameter and initial atomic states to play central roles in the nonclassical features and the degree of entanglement. 相似文献
15.
Preparation and control of entangled states in the two-mode coherent fields interacting with a moving atom via two-photon process 下载免费PDF全文
We investigate the preparation and the control of entangled
states in a system with the two-mode coherent fields interacting
with a moving two-level atom via the two-photon transition. We
discuss entanglement properties between the two-mode coherent
fields and a moving two-level atom by using the quantum reduced
entropy, and those between the two-mode coherent fields by using
the quantum relative entropy. In addition, we examine the
influences of the atomic motion and field-mode structure
parameter $p$ on the quantum entanglement of the system. Our
results show that the period and the duration of the prepared
maximal atom-field entangled states and the frequency of maximal
two-mode field entangled states can be controlled, and that a
sustained entangled state of the two-mode field, which is
independent of atomic motion and the evolution time, can be
obtained, by choosing appropriately the parameters of atomic
motion, field-mode structure, initial state and interaction time
of the system. 相似文献
16.
A.-S. F. Obada F. A. Mohammed H. A. Hessian A.-B. A. Mohamed 《International Journal of Theoretical Physics》2007,46(4):1027-1044
In this paper, we study the time evolution of the entropies and the degree of entanglement in the mixed state for a multi-quanta
JC model taking into consideration Stark shift and Kerr-like medium effect, we use a numerical method to investigate the time
evolution of the partial entropy of the atom and field subsystem. This is done in the framework of the multi-quanta presses
JC model with both the Stark shift and Kerr-like medium effect added. Furthermore, we examine the effect of the superposition
states and a statistical mixture of coherent states as an initial field on the entropies and entanglement. Our results show
that the setting of the initial state play an important role in the evolution of the sub-entropies and entanglement. 相似文献
17.
We investigate the entanglement dynamics in a bipartite atomic system subjected to thermal environment with arbitrary initial pure entangled states. We consider the atoms close together and study the effect of temperature of the reservoir and the interatomic distance on the evolution of entanglement for both initially entangled and unentangled states. We find that we can have long time entanglement even in thermal environment. 相似文献
18.
Entanglement and coherence of a three-level atom in Λ configuration interacting with two fields 下载免费PDF全文
We investigate the entanglement of a three-level atom in λ
configuration interacting with two quantized field modes by using
logarithmic negativity. Then, we study the relationship of the
atomic coherence and the entanglement between two fields which are
initially prepared in vacuum or thermal states. We find that if the
two fields are prepared in thermal states, the atomic coherence can
induce the entanglement between two thermal fields. However, there
is no coherence-induced entanglement between two vacuum fields. 相似文献
19.
E. M. Khalil 《International Journal of Theoretical Physics》2013,52(4):1122-1131
The atomic and the field entropies of a two-level atom, which is additionally driven by an external classical field are investigated. Under a certain canonical transformation for the excited and ground states the system is transformed into the usual JCM. Using the equations of motion in the Heisenberg picture exact solutions for the time-dependent dynamical operators are obtained. The entanglement between atom-field system is studied by using the atomic and the field entropies. Also we use the concurrence to detect the sudden death phenomenon and the relationship between entropies and the concurrence of the entanglement are discussed. It is shown that the amount of entanglement, the atomic and the field entropies of the subsystem can be improved by controlling the external classical field. 相似文献
20.
三能级原子与奇偶纠缠相干光作用的光场压缩 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V型三能级原子与双模奇偶纠缠相干光场相互作用过程中的光场压缩效应,讨论了压缩效应与双模奇偶纠缠相干光场的纠缠程度、系统失谐量、双模光场的平均光子数和原子基态概率幅的依赖关系。结果表明:光场压缩效应与双模奇偶纠缠相干光场的纠缠程度、失谐量、平均光子数和原子初态相关联:双模纠缠相干光场处于非纠缠状态时的光场压缩量比光场处于纠缠状态时要大;原子处在单纯的基态或激发态时光场都有明显的压缩现象出现;而原子初态中基态和激发态的概率幅较接近时无光场压缩现象;无论光场是否处于纠缠态,只有两模平均光子数接近时,光场才会出现压缩效应。 相似文献