共查询到19条相似文献,搜索用时 109 毫秒
1.
研究了劣腔内二能级原子与单模腔场的双光子相互作用,腔内原子受外加固相干光场驱动,并向一般真空态自发辐射,通过腔镜内腔内注入压缩真空态光场,使腔模向压缩真空态光场衰减,本文利用劣腔近似条件得到原子约化密度算符主方程,在此基础上讨论了二能级原子的双光子共振荧光光谱。 相似文献
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在低Q值腔内,原子相干态在一些特定时刻可以演化为原子薛定谔猫态.讨论了在这种原子薛定谔猫态中原子角动量的涨落和高阶涨落.根据不确定性原理,进一步研究了原子角动量的压缩和高阶压缩性质及其演化.研究表明,原子薛定谔猫态可以被压缩到二阶和六阶,但不能被压缩到四阶.当原子薛定谔猫态中被叠加的原子相干态数为无限多项时,其压缩特性与原子相干态相同.
关键词:
原子相干态
薛定谔猫态
角动量压缩
Bloch态 相似文献
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利用原子-腔场喇曼相互作用制备纠缠压缩真空态 总被引:2,自引:2,他引:0
提出了利用量子态腔场与原子的喇曼相互作用制备纠缠压缩真空态的方案.在该方案中,一个初始制备在基态的原子被依次送入几个初始制备在压缩真空态的微腔中.通过控制原子的运行速度,使原子与每一个腔具有相同的相互作用时间.当原子与腔场发生相互作用,原子与腔场产生纠缠之后,进行原子的测量.当原子被测量处于基态或激发态时,按照量子力学波包塌缩原理,腔场态将塌缩到相应的纠缠压缩真空态.对纠缠压缩真空态的纠缠性质也进行了简略的讨论. 相似文献
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研究了利用相干陷落方法在单原子微激射器中产生具有四阶压缩和振幅平方压缩性质的稳态腔场.结果表明,在目前微激射器实验的腔损条件下,如果注入腔中的原子初始处于相干态,只要原子束的通量适当大,当原子在腔中的飞行时间满足陷落条件时,腔场可进入相干陷落态,此时腔场呈现稳定的四阶压缩和振幅平方压缩性质
关键词: 相似文献
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操作腔外原子可控制腔内原子的压缩特性 总被引:1,自引:1,他引:0
原子偶极压缩效应的研究一直是量子光学领域中的一个十分活跃的课题,而且这些研究中多限于初始处于单原子的单态或叠加态、双原子的直积态或相干态与光场的相互作用.近年来,原子的纠缠态引起了人们极大的研究兴趣.因为纠缠态不仅证明了量子力学的非局域性,而且被广泛应用于量子计算、量子密码术、量子隐形传态等方面.最近, Yang等人研究了初始处于EPR态的两个两能级原子,其中一个注入真空态腔中,然后通过对腔外原子的操作可以控制腔内原子的发射性质.Lin等人考虑了初始处于GHZ态的三个两能级原子,让其中两个原子分别注入两个处于真空态的共振腔中.在本文中,我们分别考虑原子初始处于EPR态或GHZ态,将其中一个或两个原子同时注入一个处于相干态的光腔中,在共振条件下通过操纵腔外原子来研究腔内原子的偶极压缩效应.结果表明:对腔外原子执行一次旋转操纵和测量,可以改变腔内原子存在的偶极压缩特性.这方面的研究工作对量子态的制备和腔场的辐射控制具有一定的实际意义. 相似文献
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Kerr介质对光场压缩效应的影响 总被引:1,自引:1,他引:0
通过对一个充满Kerr介质的高Q腔中的级联三能级原子与单模相干态场相互作用系统中,光场的压缩效应的研究,利用数值计算的方法讨论了Kerr介质对光场压缩的影响,以及Kerr介质存在时,激发强度及耦合系统与光场压缩的关系。 相似文献
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本文研究了利用双级联型四能级原子实现高纯度、强的双模腔场压缩纠缠态。考虑将四能级联型原子注入至一个双模腔中,腔场与原子能级形成共振的相互作用。在原子-腔场弱相互作用下,若原子自发辐射速率远大于腔场的衰减速率,在腔场相干时间内将原子视为腔场的外部环境库,我们推导出腔场所满足的主方程。通过分析主方程并发现:在不考虑腔场真空耗散的情况下,腔场等效地与一个双模压缩真空库耦合,因此在稳态区域处于纯的双模压缩真空态,并且压缩程度只依赖于原子初始上能级的布居;在考虑腔场耗散的情况下,耗散对其纯度的影响大于对纠缠的影响;与单通道原子库情况比较,利用双通道的原子库可以有效地提高腔场的纠缠和纯度。 相似文献
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考虑两个初始处于纠缠态的A型三能级原子,将其中一原子注入双模腔中与光场发生共振相互作用的情况.采用数值计算方法,研究了对腔外原子的选择测量对腔内原子偶极压缩效应的影响.研究结果表明:采用选择原子测量方法,通过对腔外原子进行选择性测量,可增强腔内原子的偶极压缩效应. 相似文献
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考虑初始处于EPR态的两个二能级原子A、B,将B原子注入处于真空态和单光子态的叠加态的腔中,演化一段时间后,对B原子进行选择性测量,通过选择合适的腔场初始叠加状态和演化时间,可控制原子A的偶极矩压缩效应. 相似文献
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Controlling dipole squeezing of two atoms inside a cavity via manipulating an atom outside the cavity 总被引:3,自引:0,他引:3 下载免费PDF全文
Considering that three two-level atoms are initially in the GHZ single state and two of the atoms are simultaneously put into a cavity initially in the coherent state, we investigate the dipole squeezing properties of the two atoms inside the cavity under the condition of resonant interaction. It is shown that dipole squeezing properties of the two atoms inside the cavity are strongly affected by rotation manipulating of the atom outside the cavity. 相似文献
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Xiao-Juan Liu An Luo Zhao-Hui Peng Chun-Xia Jia Chun-Lei Jiang Bing-Ju Zhou 《International Journal of Theoretical Physics》2018,57(1):138-147
Considering two two-level atoms initially in Bell state, we send one atom into a vacuum cavity while leaving the other outside, and consider the motion of atom inside the cavity. Using quantum information entropy squeezing theory, the time evolution of the entropy squeezing factor of atom inside the cavity is discussed for two cases, i.e., before and after performing rotation operations and measuring atom outside, the influences of the field mode structure and atomic motions on the atomic entropy squeezing are evaluated. It is shown that atom inside the cavity has no entropy squeezing phenomenon before operating atom outside the cavity. However, the optimal entropy squeezing phenomenon of period T = 2π/p emerges and constant entropy squeezing phenomenon can occur by adjusting rotation operation to R(π/4), and setting the field mode structure parameter 0 < p < 50. In particular, if choosing p > 50, a sustained optimal entropy squeezing state (SOESS) can be generated. We also present the schematic circuit diagram of preparation of SOESS. Our proposal provides a possible way for the initial decoherent state recovering into sustained maximal coherent superposition state of single atom in the quantum noise environment. 相似文献
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本文研究了任意初态的双光子Jaynes-Cummings模型的一般演化规律,着重于分析初始原子相干性对辐射场压缩行为的影响,作为例子,讨论了一个任意初态的二能级原子与真空态和相干态光场相互作用时辐射场的压缩.数值计算了各种条件下辐射场压缩的时间演化. 相似文献
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双光子Jaynes—Cummings模型中初始原子相干性对辐射场... 总被引:2,自引:0,他引:2
本文研究了任意初态的双光子Jaynes-Cummings模型的一般演化规律,着重于分析初始原子相干性对辐射场压缩行为的影响,作为例子,讨论了一个任意初态的二能级原子与真空态和相干态光场相互作用时辐射场的压缩.数值计算了各种条件下辐射场压缩的时间演化. 相似文献
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In this paper we consider a system of two two-level atoms interacting with a binomial field in an ideal cavity. We investigate the time evolution of the single atom entropy squeezing, atomic inversion and the linear entropy for the present system. Furthermore, the relationship between the entropy squeezing and the entanglement is investigated. It is shown that the amounts of the nonclassical effects exhibited in the entropy squeezing are dependent on the different initial conditions. The entropy squeezing can give information on the corresponding linear entropy. 相似文献
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Shi-Biao Zheng 《Optics Communications》2007,273(2):460-463
We propose a scheme to realize strong squeezing for a cavity field with a single three-level atom. In the scheme the atom is sent through the cavity initially filled with a coherent field. The atom dispersively interacts with the cavity field, which is displaced by a microwave resource during the interaction. Then, a selective measurement on the atom collapses the field to a superposition of an even coherent state with a vacuum state, which exhibits strong squeezing. The scheme can also be generalized to the two-mode case. 相似文献
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A scheme for preparation of the two-atoms entangled state via the resonant interaction of a quantized cavity field with atom is presented. It is injected an two-level atom initially prepared in the superposition of the ground state and excited state through the cavity prepared in the vacuum state. The atom passing through the cavity creates atom-field entanglement. The second two-level atom prepared in the ground state is injected into the cavity at different angle. After the interaction with the cavity field, the two-atoms entangled state is produced and the cavity field is still in the vacuun state. Comparing with the existing schemes, ours is easier to realize experimently. 相似文献
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Entropy squeezing of the field interacting with a nearly degenerate V-type three-level atom 下载免费PDF全文
The position- and momentum-entopic squeezing properties of the optical field in the system of a nearly degenerate three-level atom interacting with a single-mode field are investigated. Calculation results indicate that when the field is initially in the vacuum state, it may lead to squeezing of the position entropy or the momentum entropy of the field if the atom is prepared properly. The effects of initial atomic state and the splitting of the excited levels of the atom on field entropies are discussed in this case. When the initial field is in a coherent state, we find that position-entropy squeezing of the field is present even if the atom is prepared in the ground state. By comparing the variance squeezing and entropy squeezing of the field we confirm that entropy is more sensitive than variance in measuring quantum fluctuations. 相似文献