A Four-Dimensional Measurement Scheme for Single Photon Time-Polarization

We propose an experimental scheme to realize the four-dimensional projective measurements tor a single photon. The photon polarization and time-energy provide the four-dimensional Hilbert space. Based on this scheme, we suggest an experiment to test the violation of Bell inequalities of four-dimensional systems. In addition, by virtue of a maximally entangled biphoton state, we also show that it is possible to construct a quantum key distribution channel that can provide two-bit key with one pair of entangled photons.     

A protocol to transform Svetlichny's genuine multipartite correlations into standard isotropic form

The standard isotropic correlations are widely used in the research of no-locality of quantum physics. We prove that any multipartite no-signaling correlation can be transformed into standard isotropic form through a randomization procedure, which does not change Svetlichny’s genuine multipartite correlation. For the tripartite correlations, each part with two inputs and two outcomes, we explicitly give the protocol and the proof of its validity. We then generalize the protocol to deal with the case of an N-partite.     

Partial Transposition on Bipartite System

Many properties of partial transposition are unclear as yet. Here we carefully consider the number of the negative eigenvalues of ρ^T （ρ＇s partial transposition） when p is a two-partite state. There is strong evidence to show that the number of negative eigenvalues of ρ^T is N（N - 1）/2 at most when ρ is a state in Hilbert space C^N × C^N. For the special case, the 2 × 2 system, we use this result to give a partial proof of the conjecture ｜ρ^T｜^T ≥0. We lind that this conjecture is strongly connected with the entanglement of the state corresponding to the negative eigenvalue of ρ^T or the negative entropy of ρ.     

Local distinguishability by projective measurement

This paper proves that a set of orthogonal pure states are indistinguishable by restricted local projective measurement and classical communication if the sum of their Schmidt ranks is larger than the dimension of their joint Hilbert space. This result is useful in determining the local distinguishability of quantum states and is stronger in some respects than that of Hayashi et al [Phys. Rev. Lett. 96, 040501]. In addition, it presents a new method to determine the local distinguishability of orthogonal states by projecting measurement operators into their subspaces.     

A protocol to transform Svetlichny＇s genuine multipartite correlations into standard isotropic form

The standard isotropic correlations are widely used in the research of no-locality of quantum physics. We prove that any multipartite no-signaling correlation can be transformed into standard isotropic form through a randomization procedure, which does not change Svetlichny＇s genuine multipartite correlation. For the tripartite correlations, each part with two inputs and two outcomes, we explicitly give the protocol and the proof of its validity. We then generalize the protocol to deal with the case of an N-partite.     

一维均匀势场中含时薛定谔方程的求解

本文详细讨论了一维均匀势场中含时薛定谔方程的求解.求解的思想是以均匀势场中经典粒子的运动作为参考，从经典粒子的运动轨迹出发，构建出量子情形下描述粒子运动的高斯波包形式的演化波函数，进而借助含时薛定谔方程确定波函数的具体形式.在上述思想指导下，推导得出了坐标表象和动量表象下均匀势场内一维粒子的传播子函数.同时，作为比较，狄拉克态矢量符号提供了另一种得到上述传播子函数的途径.