The role of auxiliary states in state discrimination with linear optical evices

利用资源态改进量子信道判别

Improving quantum channel discrimination with resourceful states

该研究证明在任何状态资源理论中，鲁棒性度量可精确量化量子信道判别问题中（含或不含辅助系统）使用资源态带来的最大平均成功概率提升，为资源在判别任务中的优势提供了完整刻画。

Discrimination of the Bell states of qudits by means of linear optics

The question of the discrimination of the Bell states of two qudits (i.e., d-dimensional quantum systems) by means of passive linear optical elements and conditional measurements is discussed. A qudit is supposed to be represented by d optical modes containing exactly one photon altogether. From recent results of Calsamiglia it follows that there is no way how to distinguish the Bell states of two qudits for d>2 - not even with the probability of success lower than one - without any auxiliary photons in ancillary modes. Following the results of Carollo and Palma it is proved that it is impossi…

Quantum Algorithm for Quantum State Discrimination via Partial Negation and Weak Measurement

The quantum state discrimination problem is to distinguish between non-orthogonal quantum states. This problem has many applications in quantum information theory, quantum communication and quantum cryptography. In this paper a quantum algorithm using weak measurement and partial negation will be proposed to solve the quantum state discrimination problem using a single copy of an unknown qubit. The usage of weak measurement makes it possible to reconstruct the qubit after measurement since the superposition will not be destroyed due to measurement. The proposed algorithm will be able to determ…

线性光学与光电探测实现近最优的无歧义相干态判别

Linear optics and photodetection achieve near-optimal unambiguous coherent state discrimination

针对相干态无歧义判别接收机难以实际实现的问题，本文提出基于无源线性光学、相空间位移、真空辅助模和开关光子探测的理论，并证明其在部分情形下可达到近最优性能。

Requirement of Dissonance in Assisted Optimal State Discrimination

A fundamental problem in quantum information is to explore what kind of quantum correlations is responsible for successful completion of a quantum information procedure. Here we study the roles of entanglement, discord, and dissonance needed for optimal quantum state discrimination when the latter is assisted with an auxiliary system. In such process, we present a more general joint unitary transformation than the existing results. The quantum entanglement between a principal qubit and an ancilla is found to be completely unnecessary, as it can be set to zero in the arbitrary case by adjusting…

Assisted optimal state discrimination without entanglement

A fundamental problem in quantum information is to explore the roles of different quantum correlations in a quantum information procedure. Recent work [Phys. Rev. Lett., 107 (2011) 080401] shows that the protocol for assisted optimal state discrimination (AOSD) may be implemented successfully without entanglement, but with another correlation, quantum dissonance. However, both the original work and the extension to discrimination of $d$ states [Phys. Rev. A, 85 (2012) 022328] have only proved that entanglement can be absent in the case with equal a \emph{priori} probabilities. By improving the…