【作者】 吴韬；

【导师】 叶柳； 倪致祥；

【作者基本信息】 安徽大学 ， 原子与分子物理， 2007， 硕士

【摘要】 量子信息学是量子力学和信息科学相结合的产物，它主要利用微观粒子作为载体，凭借量子力学所特有的一些性质解决一些经典信息所不能够完成的信息处理功能，充分显示了经典信息科学无法比拟的优势。量子信息学主要包括量子通信和量子计算两个部分，其中量子通信是量子信息学的重要分支，包括量子隐形传送、量子密集编码、量子秘密分享等。为了对量子信息进行处理，我们需要构造能对量子比特操作的量子硬件，其中腔量子电动力学(腔QED)方案是最有前景的量子硬件设计方案之一。腔QED进行量子信息处理操作简单，利用微腔结构可使其扩展、集成。目前，人们对量子信息处理过程的研究主要还是停留在理论阶段，所以寻找更有利于实验实现的量子信息处理过程对量子信息的发展具有非常重要的意义。在量子信息学中，量子态的传送是其中一个非常重要的研究领域，本文研究了基于腔QED技术实现量子信息的传送过程，同时对SQUIDs和腔场的相互作用也进行了一些初步研究，取得如下结果1、提出了基于原子和腔场的大失谐相互作用传送未知两原子纠缠态和两原子直积态的方案，并且我们的方案可以推广到传送N个原子的情况。我们的方案不需要贝尔态测量。同时该方案仅包含原子和腔场的大失谐相互作用，可以有效克服光场消相干影响，而且在原子通过腔的过程中，腔场只是虚激发，不需要在原子和腔之间传递量子信息，这样对腔的品质因子的要求大大的降低了。2、提出了基于单原子和腔场共振相互作用传送双模腔场纠缠态的方案，我们的方案既不需要贝尔态测量，也不需要任何操作重构纠缠初态，并且传送成功地概率为1，并且可以在腔场和腔场之间建立一个传送量子信息的量子网络。该方案也可以推广到传送N个模腔场纠缠态的情况。同时这个方案也可以用来成功地传送未知两原子纠缠态，也可以在原子和原子之间建立传送量子信息的量子网络，并推广到传送N个原子纠缠态的情况。3、提出了基于单原子和腔场的共振相互作用传送未知两原子直积态的方案，这个方案不需要贝尔态测量，也不需要任何操作重构纠缠初态，并且传送成功的概率为100％。同时该方案能够推广到传送n个原子的直积态。4、提出了基于多个原子同时和腔场发生共振作用传送未知两原子纠缠态的方案。这个方案仅包含多个原子和腔场的相互作用，腔场不用来存储量子信息，并且原子和腔场作用时间极短，量子信息可以直接地、百分之百地进行传送。5、提出了基于SQUIDs和腔场的大失谐相互作用传送量子信息的方案，此方案可以直接地、百分之百地实现量子信息的传送。该方案中腔场和SQUIDs系统之间没有量子信启、的传递，腔场只是虚激发，这样对腔的品质因子的要求大大的降低了。同时也可以在SQUIDs之间建立传送量子信息的量子网络。更多还原

【Abstract】 Quantum information theory is an inter-discipline of quantum mechanics and information theory, which is competent in some of impossible task within the classical information science. Quantum information theory shows the superiorities beyond compare in classical information. Quantum information theory includes quantum computation and quantum communication, quantum communication is a way of effective information transmission using quantum state as information unit, including quantum teleportation, quantum dense coding, quantum secret sharing, etc.In order to implement quantum information processing, we need construct the hardware of operating qubit, cavity QED is one of the most promising candidates serving as hardware of quantum information. One of the distinct advantages of quantum information processing in the context of cavity QED is that the manipulation is very simple, and the system is easy to scalable. Up to now, quantum information processing in cavity QED is mainly in the theoretical stage, thus it is extremely important to find experimental feasible scheme for quantum information processing in the context of cavity QED. Transferring of quantum information is an important researched branch of quantum information, in this paper, quantum information transfer in cavity QED is studied, transferring of quantum information via SQUIDs-cavity field interaction is studied too, some mainly results including1. We propose schemes for transferring an unknown atomic entangled state and a two-atom product state in cavity QED. Our schemes do not require Bell-state measurement. Meanwhile the schemes only involve atom-field interaction with a large detuning and do not require the transfer of quantum information between the atoms and cavity. During the passage of the atoms the cavity is only virtually excited; thus the requirement on the quality factor of the cavity is greatly loosened. The schemes can also be extended to transfer entangled state of N-atom.2. A scheme for transferring of a two-mode entanglement of zero-and one-photon entangled states between two cavities via atom-cavity field resonant interaction is proposed. This scheme does not require Bell-state measurement and performing any transformations to reconstruct the initial state. And the transfer can occur with 100% success probability in a simple manner. And a network for transfer of a two-mode entangled state between cavities is suggested. This scheme can also be extended to transfer A-mode entangled state of cavity. This scheme can also be used to transferring an unknown atomic entangled state.3. A simple scheme for transferring of a two-atom product state based on atom-cavity field resonant interaction is proposed. The scheme does not require performing any transformations to reconstruct the initial state and does not require Bell-state measurement. In addition, the transfer of the scheme has a successful probability of 100 percent in a simple manner. And the scheme can also be extended to transfer product state of n-atom.4. We present a scheme for transferring two-atom quantum state with a single resonant interaction. The scheme only requires a single resonant interaction of the atoms with a cavity mode and does not use the cavity mode as the memory. Thus the scheme is very simple and the interaction time is very short, which is important in view of decoherence. Quantum state can be directly transferred from two atoms to the other two atoms with a successful probability of 100%.5. We also present a scheme for transferring Quantum information of two superconducting quantum interference device (SQUID) qubits in cavity QED to another two SQUID qubits. In the scheme the quantum information can be directly transferred with a successful probability of 100% in a simple manner. In addition, no quantum information is transferred between the SQUIDs and the cavities, the cavity-fields are only virtually excited, thus the requirement on the quality factor of the cavities is greatly relaxed. And meanwhile we can establish a network for transferring quantum information between SQUID qubits.更多还原