量子纠缠态产生及其纯化的理论研究
文献类型：学位论文
| 作者 | 宋新国 |
| 学位类别 | 硕士 |
| 答辩日期 | 2005 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 冯勋立 |
| 关键词 | 量子纠缠 量子态的产生 纠缠纯化 |
| 其他题名 | Theoretical Investigation of Generation and Purification of Quantum Entanglement |
| 中文摘要 | 在迅速发展的量子物理领域，量子纠缠的研究一直是一个活跃的研究课题。一方面，量子纠缠被认为是当今量子物理的基本概念，它展示了许多经典信息领域所没有的特征，典型的特性包括量子非局域性和相干性等等，另一方面，量子纠缠在量子信息和量子计算领域失学着重要的角色，已被作为量子信息传送和量子信息处理的资源广泛应用于量子信息领域的各个方面，例如量子隐形形态、量子稠密编码和量子密码术等等。因此，对量子纠缠的深入研究，不仅有助于人们对量子信息和量子力学的基础理论的认识，而且有助于对量子创造的潜在应用的探索。攻读硕士学位期间，我的科研工作卞要获得以下几本方面的成果：1．利用原子与腔场相互作用的腔量子电动力学方法提出了一个产生多个双模腔纠缠态的方案。一个处于简并高激发态的相抿叠加态的V型三能级原子依次通过多个双模腔，通过对原子的能级状态的测量可以概率地产生多个双模腔纠缠态。我们产生的是W型多腔模量子纠缠态，该类型的量子纠缠态具有多重纠缠的特性，因而在量子送信以及量子计算中有着广阔的应用前景。2．基于双光子偏振的无破坏宇称测量我们提出了一种混合态纠缠纯化方案。这种方案有以下几个方面的优点：首先，我们的方案没有用到受控非门操作，而是利用双光子偏振的宇称无破坏测量装置，我们方案的成功概率几乎达到了cN方案的成功概率，比海建伟等纯化实验方案的成功概率几乎增加一倍；其次，我们的方案采用的是普通的光子探测器，避免了潘建伟等方案要求的单光子探测器，因而更加实用。3．进一步分析了基于Toffoli门操作纯化混合纠缠态的方案，研究了操作和测量过程中潜在的不完善因素对该纯化方案以及纯化后所得态的影响。发现利用三比特Toffo11门实施量子纠缠态的纯化的方案有着较高的容错闭值。与Bennett等标准纯化方案比较，操作和测量过程中潜在的不完善因素对该纯化方案的影响相对较小。这一结论对实验操作过程ll有着重要的指导意义。 |
| 英文摘要 | In the rapidly developing field of quantum information, investigation of quantum entanglement is always a very active research subject. On the one hand, quantum entanglement is recognized nowadays as a cornerstone in the fundamental of quantum physics. It displays many properties that don't exist in the classical world. Well-known properties include quantum nonlocality and interference etc. On the other hand, quantum entanglement plays a key role in the field of quantum information and quantum computation and it is recognized as a powerful resource of diverse applications in quantum information and computation, such as quantum teleportation, quantum superdense coding, and quantum cryptography. Therefore, investigation of quantum entanglement can not only give us an overall comprehension about the fundamental theory of quantum physics but also provide us the potential applications. In this paper the generation and purification of quantum entanglement are investigated The main works results of this paper are shown as follows: Based on cavity quantum electrodynamics, a scheme for the generation of entangled states of many spatially separated bimodal cavities is presented. A V-type three-level atom, initially prepared in a coherent superposition of its excited states, is successively sent into the bimodal cavities and then is measured by a field ionization detector. Depending on the result of the field ionization detector, an entangled state of many cavity modes can be generated. The entangled states obtained in our scheme belong to the W-class of entangled states, which provide potential applications in the field of quantum information and quantum communication. By using the two-mode polarization nondemolition parity detectors (QND parity detectors), instead of CNOT gate operations, an entanglement purification protocol for mixed entangled states of photons is proposed. Our protocol has some advantages: (i) Without use of the CNOT operations, the efficiency of our protocol can nearly approach that of the CNOT protocol. The total successful probability of our protocol can be nearly enhanced to the quantity twice as large as that of the linear-optics-based protocol; (ii) The sophisticated single-photon detectors are not necessary in our protocol. 3. The entanglement purification protocol based on Toffoli operations is further analyzed in the case of imperfect local operations and measurements and found that this protocol allows of higher error threshold value. Compared with the standard entanglement purification proposed by Bennett et al., it is turned out that this protocol is remarkably robust against the influences of imperfect local operations and measurements. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16462]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 宋新国. 量子纠缠态产生及其纯化的理论研究[D]. 中国科学院上海光学精密机械研究所. 2005. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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