多光子图态的制备与研究

【作者】 周晓祺；

【导师】 潘建伟； 杨涛；

【作者基本信息】 中国科学技术大学 ， 原子与分子物理， 2008， 博士

【摘要】 本文主要介绍了我们在多光子图态制备方面以及与多光子图态相关的一些的工作。我们发展了多光子纠缠技术,利用高亮度的纠缠光子对,在国际上首次实现了六光子图态的制备。我们制备出两种六光了图态——六光了GHZ态和六光子cluster态。前者是目前为止最大的光子薛定谔猫态,后者则是目前为止粒子数最多的一次性量子计算机。我们通过研究多光子图态的纠缠性质,首次在实验上演示了基于混态的GHZ型佯谬,证明了即使在混态情况下,仍然能以GHZ定理的形式揭露量子力学与定域实在论的矛盾。我们制备的混态正好等于一个较大图态中的部分粒子组成的混态,这样我们的实验就揭示了图态在粒子丢失后仍然保留的极强的非定域性。除了上面两个主要工作外,本文还介绍了几个与多光子图态相关的工作。我们利用三光子图态资源在实验上实现了量子密钥共享和量子受控密码方案。我们还在实验上首次实现了对任意未知量子态的最优非对称克隆和远端克隆。最后,我们还提出了一个基于图态的多人协作量子计算的理论方案。我们相信,在我们实验中发展起来的技术将在线性光学量子计算、远程量子通讯、量子力学基础检验等科学问题的研究中起到重要作用。更多还原

【Abstract】 In the present dissertation,we mainly describe the experiments of generating multi-photon graph states and some other related work.We developed the technique of producing entangled photon pairs.At this foundation,we have realized two special graph states,the six-photon GHZ state, the largest photonic Schr(?)dinger cat so far,and the six-photon cluster state—a state-of-the-art one-way quantum computer.We have for the first time realized a GHZ-type violation of local realism by using a mixed state.Our mixed state is equivalent to the partial,qubit-loss state of an N-qubit cluster.As a result,the GHZ-typc violation of local,realism by the mixed state also exhibits the robustness of cluster states under qubit-loss conditions.In addition to the above two major work:this dissertation also introduced some other related work.By using the three-photon entanglement resources,we successfully realized the quantum secret sharing protocol and the third-man cryptography protocol.We also have for the first time realized optimal asymmetrical cloning and telecloning of an unknown state.At last,we present a aovel scheme based on graph states to solve the quantum computation problem which requires many people’s cooperation.We believe that the techniques developed in our work would greatly facilitate the progresses in many fields of scientific rcscarch which include linear optical quantum computation,long distance quantum communication and the test of foundation of quantum mechanics.更多还原