北京大学王剑威团队取得一项新进展。他们提出了集成微梳中的连续变量多部纠缠。相关论文于2025年2月19日发表在《自然》杂志上。

据悉，大规模纠缠态的产生对量子计算、通信和计量等量子技术至关重要。集成量子光子学能够在芯片上对量子光态进行编码、处理和检测，为大规模纠缠态的产生和操纵提供了一个很有前途的平台。在单光子内离散变量编码的量子位之间产生纠缠是具有挑战性的，因为难以使单光子在光子芯片上相互作用。使用连续变量操作的设备更有前途，因为它们能够确定地产生和纠缠模，其中信息以光正交编码。迄今为止的证明仅限于两个拟模态之间的纠缠。

该课题组人员报告了在集成光学芯片上确定产生连续变八模纠缠。该芯片提供了一个量子微梳，可以产生低于阈值的多模压缩真空光学频率梳。该课题组验证了它们的八模态的不可分性，并通过违反van lock-furthemawa标准证明了在数百兆赫边带频率上的超模多部纠缠。通过测量具有足够低的非对角噪声的无效相关的完整矩阵，该课题组描述了多歧的缠结结构，其近似于期望的有限挤压的簇型结构。

这项工作显示了连续变量集成光子量子器件，在促进量子计算、网络和传感方面的潜力。

附：英文原文

Title: Continuous-variable multipartite entanglement in an integrated microcomb

Author: Jia, Xinyu, Zhai, Chonghao, Zhu, Xuezhi, You, Chang, Cao, Yunyun, Zhang, Xuguang, Zheng, Yun, Fu, Zhaorong, Mao, Jun, Dai, Tianxiang, Chang, Lin, Su, Xiaolong, Gong, Qihuang, Wang, Jianwei

Issue&Volume: 2025-02-19

Abstract: The generation of large-scale entangled states is crucial for quantum technologies, such as quantum computation1, communication2 and metrology3. Integrated quantum photonics that enables on-chip encoding, processing and detection of quantum light states offers a promising platform for the generation and manipulation of large-scale entangled states4,5. Generating entanglement between qubits encoded in discrete variables within single photons is challenging, owing to the difficulty of making single photons interact on photonic chips6,7,8,9,10,11. Devices that operate with continuous variables are more promising, as they enable the deterministic generation and entanglement of qumodes, in which information is encoded in light quadratures. Demonstrations so far have been limited to entanglement between two qumodes12,13,14,15,16,17,18,19,20. Here we report the deterministic generation of a continuous-variable eight-mode entanglement on an integrated optical chip. The chip delivers a quantum microcomb that produces multimode squeezed-vacuum optical frequency combs below the threshold. We verify the inseparability of our eight-mode state and demonstrate supermode multipartite entanglement over hundreds of megahertz sideband frequencies through violation of the van Loock–Furusawa criteria. By measuring the full matrices of nullifier correlations with sufficiently low off-diagonal noises, we characterize multipartite entanglement structures, which are approximate to the expected cluster-type structures for finite squeezing. This work shows the potential of continuous-variable integrated photonic quantum devices for facilitating quantum computing, networking and sensing.

DOI: 10.1038/s41586-025-08602-1

Source: https://www.nature.com/articles/s41586-025-08602-1