共查询到20条相似文献,搜索用时 109 毫秒
1.
WANG Zhong-Jie 《理论物理通讯》2010,54(6):1109-1111
Several schemes have been proposed to prepare two-mode squeezed state and entanglement state between motional states of a single trapped ion and light. Preparation of two-mode squeezed state is based on interaction of a trapped ion located in light cavity with cavity field. Preparation of entanglement state is based on interaction of a trapped ion located in light cavity with cavity field and a traveling wave light field. 相似文献
2.
Sintayehu Tesfa 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(2):351-358
Squeezing properties of a two-mode
radiation produced by a process of driven degenerate parametric
down conversion, when the cavity is coupled to two independent
squeezed vacuum reservoirs employing the linearization procedure,
are analyzed. The two-mode cavity and output radiations exhibit
considerable squeezing even when the oscillator is coupled to a
vacuum reservoir. One of the effects of coupling the cavity to the
squeezed vacuum reservoirs is to increase the degree of squeezing
exponentially. For the output radiation the correlation of the
quadrature operators evaluated at different times also contributes
to the squeezing, which is the reason for quenching of the overall
noise in one of the quadrature components of the fundamental mode. 相似文献
3.
Photon-number distribution of two-mode squeezed thermal states by entangled state representation 下载免费PDF全文
Using the entangled state representation, we convert a two-mode squeezed number state to a Hermite polynomial excited squeezed vacuum state. We first analytically derive the photon number distribution of the two-mode squeezed thermal states. It is found that it is a Jacobi polynomial; a remarkable result. This result can be directly applied to obtaining the photon number distribution of non-Gaussian states generated by subtracting from (adding to) two-mode squeezed thermal states. 相似文献
4.
We show how to generate bilinear (quadratic) Hamiltonians in cavity quantum
electrodynamics (QED) through the interaction of a single driven three-level
atom with two (one) cavity modes. With this scheme it is possible to
generate one-mode mesoscopic squeezed superpositions, two-mode
entanglements, and two-mode squeezed vacuum states (such the original EPR
state), without the need for Ramsey zones and external parametric
amplification. The degree of squeezing achieved is up to 99% with currently
feasible experimental parameters and the errors due to dissipative
mechanisms become practically negligible. 相似文献
5.
Optical enhanced interferometry with two-mode squeezed twin-Fock states and parity detection 下载免费PDF全文
We theoretically investigate the quantum enhanced metrology using two-mode squeezed twin-Fock states and parity detection. Our results indicate that, for a given initial squeezing parameter, compared with the two-mode squeezed vacuum state, both phase sensitivity and resolution can be enhanced when the two-mode squeezed twin-Fock state is considered as an input state of a Mach–Zehnder interferometer. Within a constraint on the total photon number, although the two-mode squeezed vacuum state gives the better phase sensitivity when the phase shift φ to be estimated approaches to zero, the phase sensitivity offered by these non-Gaussian entangled Gaussian states is relatively stable with respect to the phase shift itself. When the phase shift slightly deviates from φ= 0, the phase sensitivity can be still enhanced by the two-mode squeezed twin-Fock state over a broad range of the total mean photon number where the phase uncertainty is still below the quantum standard noise limit. Finally, we numerically prove that the quantum Cramer–Rao bound can be approached with the parity detection. 相似文献
6.
For the first time we derive the dissipating result of an initial two-mode squeezed pure vacuum state passing through a two-mode amplitude dissipative channel described by the direct product of two independent single-mode master equations. Although these two master equations do not mix the two modes (there is no coupling between them), since the two-mode squeezed state is simultaneously an entangled state, the final state which emerges from passing this channel is a two-mode mixed density operator. The compact expression of the outcoming state is obtained, which manifestly shows that as time evolves, the squeezing effect decreases. 相似文献
7.
For the first time we derive the dissipating result of an initial two-mode squeezed pure vacuum state passing through a two-mode amplitude dissipative channel described by the direct product of two independent single-mode master equations. Although these two master equations do not mix the two modes (there is no coupling between them), since the two-mode squeezed state is simultaneously an entangled state, the final state which emerges from passing this channel is a two-mode mixed density operator. The compact expression of the outcoming state is obtained, which manifestly shows that as time evolves, the squeezing effect decreases. 相似文献
8.
借助于双模压缩真空态在EPR纠缠态表象中的表示,研究了用双模压缩真空态作为量子通道 实现任意的单模和双模量子态的远程传输.
关键词:
量子隐形传态
EPR纠缠态
压缩真空态 相似文献
9.
In this paper, we propose a scheme to generate an entangled state between two spatially separated movable mirrors by injecting the two-mode squeezed optical reservoir to the dissipative optomechanics, in which the movable mirrors can modulate the linewidth of the cavity modes. When the coupling between the mirrors and the corresponding cavity modes is weak, the two driven cavity fields can respectively behave as the squeezed-vacuum reservoir for the two movable mirrors by utilizing the effect of completely destructive interference of quantum noise. Thus the mechanical modes are prepared in a two-mode squeezed vacuum state. Moreover,when the coupling between the two mirrors and the cavities modes is strong, the entanglement between the two movable mirrors decreases because photonic excitation can preclude the completely destructive interference of quantum noise, but the movable mirrors are still entangled. 相似文献
10.
Hua-tang Tan Shi-yao Zhu M. Suhail Zubairy 《量子光学学报》2006,12(B08):83-83
We discuss the generation and evolution of entangled light in a correlated spontaneous emission laser in the linear regime. The master equation for the two-mode cavity field is derived and solved analytically in phase space. The time-dependent characteristic function in the Wigner representation for the two-mode field is obtained. It shows that the two-mode field in the cavity evolves in a two-mode Gaussian state. The entanglement degree of the two- mode field in the cavity increases initially, then decreases, and finally vanishes as the field evolves from an initial vacuum. The period of the entanglement is extended as the intensity of the driving field is increased. It is found that the entanglement still exists even when the two-mode squeezing disappears. During the entanglement period, the intensity of the field is amplified. The entanglement for the initial field being a two-mode squeezed vacuum and the entanglement of the output field are also discussed. 相似文献
11.
Continuous-variable entanglement in the interacting system of a mesoscopic Josephson junction with a squeezed field is investigated. It is shown that when the cavity field is initially prepared in a squeezed vacuum state and the junction in its lowest energy state, the coupling system can evolve into a two-mode Caussian state. The timedependent characteristic function in the Wigner representation for the system is analytically obtained, and the squeezing degree of the initial cavity field turns out to have not only an apparent enhancing but also a weakening effect on the entanglement of the coupling system under suitable parameter conditions. 相似文献
12.
The two-mode quantum electromagnetic field in the vacuum squeezed state is considered in the tomographic-probability representation.
The symplectic, center-of-mass, and photon-number tomograms for the two-mode vacuum squeezed state are obtained explicitly.
The expressions for photon statistics of the squeezed light are reconsidered using the state tomograms, and some new integral
relations are found for one and multimode orthogonal polynomials. 相似文献
13.
Quantum entanglement and nonlocality properties of a family of
two-mode Gaussian pure states have been investigated. The results
show that the entanglement of these states is determined by both the
two-mode squeezing parameter and the difference of the two
single-mode squeezing parameters. For the same two-mode squeezing
parameter, these states show larger entanglement than the usual
two-mode squeezed vacuum state. The violation of Bell inequality
depends strongly on all the squeezing parameters of these states and
disappears completely in the limit of large squeezing. In
particular, these states can exhibit much stronger violation of
local realism than two-mode squeezed vacuum state in the range of
experimentally available squeezing values. 相似文献
14.
强调双模厄米多项式在量子光学理论中的地位,认为它是研究连续变量纠缠态和压缩态的必要函数,具有明确的物理意义。利用双模厄米多项式,结合有序算符内的积分技术,给出了若干新的算符恒等式和互逆的积分变换公式,证明了压缩双模粒子数态恰好是双变量厄米多项式激发压缩真空态。 相似文献
15.
Based on the fact that a two-mode squeezed number state is a
two-variable Hermite polynomial excitation of the two-mode squeezed
vacuum state, the result of one-mode l-photon measurement for the
two-mode squeezed number state $S_2|m,n\rangle$ is discussed. It is found that a remaining field-mode simultaneously
collapses into a number state $|n-m+l\rangle$ with
the coefficient being a Jacobi polynomial of n, m and l, which manifestly exhibits the entanglement
between the two modes, i.e. it depends on the number-difference
between the two modes. The second mode collapses into an excited
coherent state when the first mode is measured as a coherent state. 相似文献
16.
E. Wu Yong Hong Ma Li Xia Zeng Xiao An Zhang 《International Journal of Theoretical Physics》2008,47(6):1600-1605
Continuous variable remote state preparation is presented using a two-mode squeezed vacuum state based on the Heisenberg representation.
We show that it is possible to remotely prepare this state in principle. Our scheme’s main advantages are: (i) It is practical,
because a two-mode squeezed vacuum state is easy achieved in experiment, and our scheme only requires a beam splitter and
a feedforward; (ii) Using our scheme decoherence and being cheating can be avoided. 相似文献
17.
18.
纠缠微波信号是电磁场微波频段量子特性的体现.在总结了现有纠缠微波信号产生及验证实验的基础上,针对目前没有统一的表达式来描述纠缠微波信号格式的问题,通过深入分析纠缠微波信号的特性,提出了两种纠缠微波信号的表示方法.一种是在量子框架下,利用双模压缩真空态表示,并分别在光子数表象下和Wigner分布下分析了其信号特征,刻画了正交分量之间的正反关联特性;另一种是在经典框架下,利用关联随机信号表示,刻画了测量后纠缠微波信号场幅度正交分量随时间变化的波形图.两种表示恰当合理地反映了纠缠微波信号连续变量纠缠的特性. 相似文献
19.
非等同两原子与双模叠加态腔场的拉曼相互作用 总被引:1,自引:0,他引:1
研究了处于双模腔中的两个非等同二能级原子与叠加态光场的拉曼相互作用,推导出了两模光场均处于光子数态和任意叠加态时腔场谱的计算公式,给出了两模初始场为相干态和压缩真空态时谱结构的数值结果,讨论了相对耦合常数R=g2/g1和初始场强对腔场谱的影响.发现腔场谱结构不仅与初始场强有关,还随初始场光子数分布的变化而改变. 相似文献