首次观测到超低温度下钠钾基态分子和钾原子碰撞的散射共振

<正>量子计算和量子模拟具有强大的并行计算和模拟能力,不仅为经典计算机无法解决的大规模计算难题提供有效解决方案,也可有效揭示复杂系统的物理规律,为新能源开发、新材料设计等提供指导~([1])。量子计算研究的终极目标是构建通用型量子计算机,但这一目标需要制备大规模的量子纠缠并进行容错计算,实现这一目标仍然需要经过长期不懈的努力。当前,量子计算的短期目标是通过发展专用型量子计算机,即专用量子     

冷原子系综内单集体激发态的相干操纵

原子系综内部分原子发生相干态转移后所处量子态被称为集体激发态.如果激发数目在单原子量级则被称为单激发态.在量子存储过程中，单光子以单激发态的形式在原子系综内进行存储.因此，研究单激发态的制备、演化、转化、干涉等过程是量子存储及其应用研究的关键.本文总结了近年来作者所在研究团队针对冷原子系综体系在此研究方向取得的若干成果.主要包括采用动量模式调控、三维光晶格等手段抑制单激发态的退相干，采用环形腔增强原子至光子的转化效率，发展基于拉曼光的单激发态相干转移技术，利用单量子态不同模式间干涉制备光与原子纠缠，利用里德伯阻塞机制提升纠缠制备效率等.此外，简要回顾了基于多个单激发态的量子中继及量子网络实验.     

果胶甲基酯酶PME参与调控大麦根尖铝毒敏感性

利用大麦耐铝品种和敏感品种来分析根尖果胶甲基酯酶（PME）在大麦铝毒敏感性中的调控作用.通过对耐铝性差异极其显著的2个大麦明品种2000-2与沪麦16经铝处理后的Morin荧光检测,观察到2000-2根尖荧光明显比沪麦16强,铝试剂比色法测定结果进一步表明,敏感品种根尖细胞壁上铝积累量比耐铝品种高,达到极显著差异（p〈0.05或0.01）.对根尖PME活性分析结果表明,与对照相比,铝处理4 h的2000-2根尖PME活性显著上升,但处理24 h后PME活性又显著下降;而沪麦16的PME活性与对照相比无显著性差异.这些结果表明细胞壁上铝积累与PME活性变化有密切的相关性,证实PME活性参与调控大麦铝毒敏感性.     

Long-distance quantum teleportation assisted with free-space entanglement distribution

Faithful long-distance quantum teleportation necessitates prior entanglement distribution between two communicated locations.The particle carrying on the unknown quantum information is then combined with one particle of the entangled states for Bell-state measurements,which leads to a transfer of the original quantum information onto the other particle of the entangled states.However in most of the implemented teleportation experiments nowadays,the Bell-state measurements are performed even before successful distribution of entanglement.This leads to an instant collapse of the quantum state for the transmitted particle,which is actually a single-particle transmission thereafter.Thus the true distance for quantum teleportation is,in fact,only in a level of meters.In the present experiment we design a novel scheme which has overcome this limit by utilizing fiber as quantum memory.A complete quantum teleportation is achieved upon successful entanglement distribution over 967 meters in public free space.Active feed-forward control techniques are developed for real-time transfer of quantum information.The overall experimental fidelities for teleported states are better than 89.6%,which signify high-quality teleportation.     

Realization of Fast All-Microwave Controlled-Z Gates with a Tunable Coupler

The development of high-fidelity two-qubit quantum gates is essential for digital quantum computing. Here,we propose and realize an all-microwave parametric controlled-Z(CZ) gates by coupling strength modulation in a superconducting Transmon qubit system with tunable couplers. After optimizing the design of the tunable coupler together with the control pulse numerically, we experimentally realized a 100 ns CZ gate with high fidelity of 99.38%±0.34% and the control error being 0.1%. We note that ...     

量子密码实验新进展--13km自由空间纠缠光子分发:朝向基于人造卫星的全球化量子通信

实验实现了纠缠光子对通过地面大气13km的自由空间分发.实验表明,纠缠光子在通过超过大气层等效厚度的距离之后,纠缠特性依然能够很好保持.文章作者观测了类空间隔Bell-CHSH不等式的破坏,其S值达到2.45±0.09.在这个基础上,我们利用分发的纠缠光子对演示了BB84-Ekert91量子密码协议.这个实验第一次验证了用纠缠光子对进行地面和卫星量子通信的可行性,为未来的基于人造卫星全球化量子通信打下坚实的基础.文章将首先回顾量子密码实验方面的最新进展,然后再详细介绍作者的实验.     

量子Zeno效应新论

本文根据量子力学的基本原理和量子测量理论给出了量子Ｚｅｎｏ效应的简要证明，阐明了该效应的物理基础，指出了该效应与系统ＣＰ破坏的关联。     

ENERGY SPECTRUM AND WAVE FUNCTION FOR MULTI-MODE COUPLED NON-IDENTICAL HARMONIC OSCILLATORS

By means of the linear quantum transformation theory, we consisely derive the exact solution including energy spectrum and wave function for multi-mode coupled non-identical harmonic oscillators.     

稀土对低温固体硼碳氮共渗作用的研究

采用Ｘ射线衍射仪,恒电位仪,摩擦磨损试验机等设备,研究了低温硼碳氮稀土（Ｂ－Ｃ－Ｎ－ＲＥ）共渗工艺及共渗层的组织性能,并与硼碳氮（Ｂ－Ｃ－Ｎ）共渗工艺及组织性能进行了比较。在适当范围内,稀土具有明显的催渗作用;与Ｂ－Ｃ－Ｎ共渗相比,Ｂ－Ｃ－Ｎ－ＲＥ共渗层的耐蚀性明显提高。对稀土元素的作用机制作了初步的探讨。     

基于量子隐形传态的完全Bell基测量

完全区分4个Bell态是实现量子隐形传态过程的关键,目前线形光学的办法还不能对Bell态进行完全的测量.我们根据两光子量子隐形传态方案利用Mach-Zehnder干涉仪,通过高位希尔伯特空间中偏振与路径之间的纠缠实现了完全bell基测量.通过引入参考光的方法,达到干涉仪两臂相位的自动稳定;该方案成功应用于16 km自由空间量子隐形传态实验中.