Unconventional Phonon Blockade in a Tavis–Cummings Coupled Optomechanical System

A phonon blockade is achieved in a hybrid optomechanical system including an ensemble of two-level quantum emitters. The introduction of the ensemble of quantum emitters sets up a mechanism of quantum destructive interference within the system, by which the phonon statistical characteristic exhibits strong antibunching under the condition of weak driving and weak coupling. By analyzing the analytic solution of the second-order correlation function, the optimal parametric condition for ideal phonon blockade effect is obtained. The numerical simulation of the second-order correlation function perfectly accord with the analytical solution. The validity of the effective Hamiltonian is proved by the numerical simulations with quantum master equation. The proposed scheme provides a possible way to realize the single-phonon source experimentally.     

Complete Bell-state and Greenberger–Horne–Zeilinger-state nondestructive detection based on simplified symmetry analyzer

We present a simplified symmetry analyzer (SA) with cross-Kerr nonlinearity, quantum non-demolition photon number measurement and basic optical elements. Based on the present symmetry analyzer (SA), all the Bell states can be discriminated nondestructively with nearly unity probability. In addition, with the help of cross-phase modulation (XPM) induced by giant cross-Kerr nonlinearity, three-photon Greenberger–Horne–Zeilinger (GHZ) state can also be discriminated determinately and nondestructively, which is supposed to be meaningful in quantum information processing.     

A realizable multi-bit dense coding scheme with an Einstein—Podolsky—Rosen channel

We propose a multi-bit dense coding scheme by using only an Einstein-Podolsky-Rosen(EPR) channel and assistant qubits.It is shown that no matter how many classical bits there are,the quantum channel is always a Bell state.The present dense coding process can also prepare non-local multi-particle Greenberger-Horne-Zeilinger(GHZ) states at one of the participants.The quantum circuits for this dense coding process are constructed,the deterministic implementation method in an optical system based on the cross-Kerr nonlinearities is shown.     

高能重离子碰撞中的J/ψ反常抑制现象

对NA50合作组给出的入射动量为158A GeV/c的Pb-Pb碰撞中的J/ψ反常抑制现象进行了分析.在J/ψ的核与随动者吸收理论基础上，假设了QGP相变在对心Pb-Pb碰撞中的产生及QGP环境对J/ψ粒子100%的吸收效应，从而改进了高能重离子碰撞中的J/ψ微分产生截面，理论较好地解释了实验结果. 关键词： J/ψ反常抑制')" href="#">J/ψ反常抑制 核吸收 随动者 夸克-胶子等离子体     

Time-bin-encoding-based remote states generation of nitrogen-vacancy centers through noisy channels

We design proposals to generate a remote Greenberger-Horne-Zeilinger(GHZ) state and a W state of nitrogenvacancy(NV) centers coupled to microtoroidal resonators(MTRs) through noisy channels by utilizing time-bin encoding processes and fast-optical-switch-based polarization rotation operations.The polarization and phase noise induced by noisy channels generally affect the time of state generation but not its success probability and fidelity.Besides,the above proposals can be generalized to n-qubit between two or among n remote nodes with success probability unity under ideal conditions.Furthennore,the proposals are robust for regular noise-changeable channels for the n-node case.This method is also useful in other remote quantum information processing tasks through noisy channels.     

新型衍生化β-环糊精液相色谱键合相拆分和测定人体血浆中普萘洛尔对映体

采用对硝基苯氨基甲酸酯衍生化6-叠氮基β-环糊精,将衍生化的配体与含炔键的SBA-15硅胶进行点击反应(Click chemistry),合成新型对硝基苯氨基甲酸酯化β-环糊精键合SBA-15硅胶手性固定相(NPCSP)。在极性有机溶剂模式下,成功实现了β-受体阻滞剂普萘洛尔对映体的快速手性分离,探讨了流动相中甲醇含量、冰醋酸与三乙胺的浓度和温度等对其手性分离的影响。优化的色谱条件为:流动相组成为乙腈-甲醇-冰醋酸-三乙胺(90∶10∶1.25∶2.25,V/V),温度为288 K,流速为0.5 mL/min,进样量为20μL,波长为290 nm。该条件下的分离度为2.04,拆分时间短(<15 min)。以氢氯噻嗪为内标,采用HPLC-MS选择离子监测模式([M+H]+m/z 260.10)定量测定血浆中普萘洛尔的含量,在2.5~250μg/L的浓度范围呈良好的线性关系,检出限(S/N=3)为1μg/L。结果表明,本手性固定相对普萘洛尔对映体具有良好的手性拆分能力,所建立的分析方法灵敏、准确、简便、快速,可用于人体血浆中普萘洛尔对映体的测定及药代动力学研究。     

General Quantum Circuits for Implementing Deterministic Entanglement Conversion

We propose explicit quantum circuits for implementing a positive operator valued measurement (POVM), by which a class of relatively general entanglement conversion can be realized determinately. Different from conventional method based on decomposition of unitary matrices, our implementation procedure involves decomposition of the evolution process from the initial state to the final state with quantum Toffoli gates.     

Two-qubit and three-qubit controlled gates with cross-Kerr nonlinearity

Schemes for two-qubit and three-qubit controlled gates based on cross-Kerr nonlinearity are proposed in this paper.The probability of the success of these gates can be increased by quantum nondemolition detectors,which are used to judge which paths the signal photons pass through.These schemes are almost deterministic and require no ancilla photon.The advantages of these gates over the existing ones include less resource consumption and a higher probability of success,which make our schemes more feasible with current technology.     

Engineering multipartite steady entanglement of distant atoms via dissipation

We propose a scheme for generating an entangled state for three atoms trapped in separate optical cavities that are coupled to each other through two optical fibers based on coherent driving and dissipation, which are induced by the classical fields and the decay of non-local bosonic modes, respectively. In our scheme, the interaction time need not be controlled strictly in the overall dynamics process, and the cavity field decay can be changed into a vital resource. The numerical simulation shows that the fidelity of the target state is insensitive to atomic spontaneous emission, and our scheme is good enough to generate the W state of distant atoms with a high fidelity and purity. In addition, the present scheme can also be generalized to prepare the N-partite W state of distant atoms.     

Scheme for Realizing Deterministic Entanglement Concentration with Atoms Via Cavity QED

A scheme for concentrating entanglement in two partially entangled Einstein-Podolsky-Rosen (EPR) pairs using repetitious resonant interactions of the atoms with a single-mode cavity field is proposed. A maximally entangled EPR pair can be deterministically extracted with the success probability of 1.0. In the scheme, the two logical states of a qubit are represented by the two lowest levels of an atom while a higher-energy intermediate level is used to facilitate the realization of the unitary operations, and all the operations required to realize deterministic entanglement concentration can be implemented in a reasonable amount of time before decoherence sets in. The scheme might be experimentally realizable with presently available cavity QED techniques and gives a realistic means to realize entanglement concentration deterministically.