Heralded linear optical quantum Fredkin gate based on one auxiliary qubit and one single photon detector

• Published in: Chinese physics B Vol. 23; no. 8; pp. 362 - 367
• Main Authors: Zhu, Chang-Hua, Cao, Xin, Quan, Dong-Xiao, Pei, Chang-Xing
• Format: Journal Article
• Language: English
• Published: 01.08.2014
• Subjects: Beneficiation; Communication networks; Detectors; Fredkin门; Gates; Networks; Photons; Qubits (quantum computing); SPD; Switching theory; 单光子探测器; 检测器; 线性光学; 通信网络; 量子比特; 量子计算
• ISSN: 1674-1056; 2058-3834; 1741-4199
• DOI: 10.1088/1674-1056/23/8/084207

Linear optical quantum Fredkin gate can be applied to quantum computing and quantum multi-user communication networks. In the existing linear optical scheme, two single photon detectors （SPDs） are used to herald the success of the quantum Fredkin gate while they have no photon count. But analysis results show that for non-perfect SPD, the lower the detector efficiency, the higher the heralded success rate by this scheme is. We propose an improved linear optical quantum Fredkin gate by designing a new heralding scheme with an auxiliary qubit and only one SPD, in which the higher the detection efficiency of the heralding detector, the higher the success rate of the gate is. The new heralding scheme can also work efficiently under a non-ideal single photon source. Based on this quantum Fredkin gate, large-scale quantum switching networks can be built. As an example, a quantum Bene~ network is shown in which only one SPD is used.