当前位置:首页 > 实验室 > 量子光学基础和应用实验室
实验室简介

量子光学以光的相干性和量子性为基本点,运用量子力学理论及现代光学与电子学实验手段,研究光场的各种非经典效应及光与物质相互作用的量子现象。

实验室通过非简并光学参量振荡与放大,分别获得了正交双模压缩真空态,强度差压缩态,明亮的量子相关EPR纠缠光束对,三组份纠缠态光场,四组份类GHZ纠缠态光场,类cluster纠缠态光场,TTPC纠缠态光场,八组份cluster纠缠态光场等多种不同性质的非经典光场。量子纠缠交换,连续变量量子保密通信,量子受控非门,量子逻辑门序列等实验研究。现正开展连续变量单向量子计算及量子网络方面研究。

最新工作

Deterministic Distribution of Multipartite Entanglement and Steering in a Quantum Network by Separable States


Authors:Meihong Wang, Yu Xiang, Haijun Kang, Dongmei Han, Yang Liu, Qiongyi He, Qihuang Gong, Xiaolong Su , and Kunchi Peng

    As two valuable quantum resources, Einstein-Podolsky-Rosen entanglement and steering play important roles in quantum-enhanced communication protocols. Distributing such quantum resources among multiple remote users in a network is a crucial precondition underlying various quantum tasks. We experimentally demonstrate the deterministic distribution of two- and three-mode Gaussian entanglement and steering by transmitting separable states in a network consisting of a quantum server and multiple users. In our experiment, entangled states are not prepared solely by the quantum server, but are created
among independent users during the distribution process. More specifically, the quantum server prepares separable squeezed states and applies classical displacements on them before spreading out, and users simply perform local beam-splitter operations and homodyne measurements after they receive separable states.We show that the distributed Gaussian entanglement and steerability are robust against channel loss. Furthermore, one-way Gaussian steering is achieved among users that is useful for further directional or highly asymmetric quantum information processing.

Phys. Rev. Lett. 125, 260506 (2020)

Experimental test of error-tradeoff uncertainty relation using a continuous-variable entangled state


Authors:Yang Liu, Zhihao Ma, Haijun Kang, Dongmei Han, Meihong Wang, Zhongzhong Qin, Xiaolong Su, and Kunchi Peng

Yang Liu, Zhihao Ma, Haijun Kang, Dongmei Han, Meihong Wang, Zhongzhong Qin,  Xiaolong Su, and Kunchi Peng

  Heisenberg’s original uncertainty relation is related to measurement effect, which is different from the preparation uncertainty relation. However, it has been shown that Heisenberg’s error disturbance uncertainty relation is not valid in some cases. We experimentally test the error-tradeoff uncertainty relation by using a continuous-variable Gaussian Einstein–Podolsky–Rosen (EPR)-entangled state. Based on the quantum correlation between the two entangled optical beams, the errors on amplitude and phase quadratures of one EPR optical beam coming from joint measurement are estimated, respectively, which are used to verify the error–tradeoff relation. Especially, the error–tradeoff relation for error-free measurement of one observable is verified in our experiment. We also verify the error–tradeoff relations for nonzero errors and mixed state by introducing loss on one EPR beam. Our experimental results demonstrate that Heisenberg’s error–tradeoff relation is violated in some cases for a continuous-variable system, while the Ozawa’s and Branciard’s relations are valid.

 

npj Quantum Information 5:68 (2019)

Characterizing the multipartite continuous-variable entanglement structure from squeezing coefficients and the Fisher information


Authors:Zhongzhong Qin, Manuel Gessner, Zhihong Ren, Xiaowei Deng, Dongmei Han, Weidong Li, Xiaolong Su, Augusto Smerzi, and Kunchi Peng

Zhongzhong Qin, Manuel Gessner, Zhihong Ren, Xiaowei Deng, Dongmei Han, Weidong Li, Xiaolong Su, Augusto Smerzi, and Kunchi Peng


   Understanding the distribution of quantum entanglement over many parties is a fundamental challenge of quantum physics and is of practical relevance for several applications in the field of quantum information. The Fisher information is widely used in quantum metrology since it is related to the quantum gain in metrology measurements. Here, we use methods from quantum metrology to microscopically characterize the entanglement structure of multimode continuous-variable states in all possible multi-partitions and in all reduced distributions. From experimentally measured covariance matrices of Gaussian states with 2, 3, and 4 photonic modes with controllable losses, we extract the metrological sensitivity as well as an upper separability bound for each partition. An entanglement witness is constructed by comparing the two quantities. Our analysis demonstrates the usefulness of these methods for continuous-variable systems and provides a detailed geometric understanding of the robustness of cluster-state entanglement under photon losses.

 

npj Quantum Information 5:3 (2019)

Demonstration of Monogamy Relations for Einstein-Podolsky-Rosen Steering in Gaussian Cluster States


Authors:Xiaowei Deng, Yu Xiang, Caixing Tian, Gerardo Adesso, Qiongyi He, Qihuang Gong, Xiaolong Su, Changde Xie, and Kunchi Peng

Xiaowei Deng, Yu Xiang, Caixing Tian, Gerardo Adesso, Qiongyi He, Qihuang Gong, Xiaolong Su, Changde Xie, and Kunchi Peng


   Understanding how quantum resources can be quantified and distributed over many parties has profound applications in quantum communication. As one of the most intriguing features of quantum mechanics, Einstein-Podolsky-Rosen (EPR) steering is a useful resource for secure quantum networks. By reconstructing the covariance matrix of a continuous variable four-mode square Gaussian cluster state subject to asymmetric loss, we quantify the amount of bipartite steering with a variable number of modes per party, and verify recently introduced monogamy relations for Gaussian steerability, which establish quantitative constraints on the security of information shared among different parties. We observe a very rich structure for the steering distribution, and demonstrate one-way EPR steering of the cluster state under Gaussian measurements, as well as one-to-multimode steering. Our experiment paves the way for exploiting EPR steering in Gaussian cluster states as a valuable resource for multiparty quantum information tasks.

 

Phys. Rev. Lett. 118, 230501 (2017)