韩国科学技术高等研究院Young-Sik Ra团队发现了三维簇纠缠态的产生。这一研究成果发表在2025年2月24日出版的《自然—光子学》杂志上。
基于测量的量子计算是一种有前景的量子计算范式，其中通用计算是通过一系列局部测量来实现的。这种方法的核心是制备多体纠缠，即簇态。虽然具有二维连通性的簇态是通用性所必需的，但三维簇态对于额外实现容错是必要的。然而，实现三维连接的挑战将簇态生成能力限制在二维以内。
研究组演示了基于光子连续变量平台的三维簇态的确定性生成。为了实现三维连接，他们利用了超快量子光的时频模式的一个关键优势：可以直接访问任意复模基，从而实现所需的连接。通过生成具有一维、二维和三维连接的簇态来证明该方法的通用性。为了完整表征它们，研究组开发了一种用于多模高斯态的量子态层析成像方法。此外，还通过无效器测量和完全不可分割性测试来验证簇态的生成。该工作为基于容错和通用测量的量子计算铺平了道路。
附：英文原文
Title: Generation of three-dimensional cluster entangled state
Author: Roh, Chan, Gwak, Geunhee, Yoon, Young-Do, Ra, Young-Sik
Issue&Volume: 2025-02-24
Abstract: Measurement-based quantum computing is a promising paradigm of quantum computation, in which universal computing is achieved through a sequence of local measurements. The backbone of this approach is the preparation of multipartite entanglement, known as cluster states. Although a cluster state with two-dimensional connectivity is required for universality, a three-dimensional cluster state is necessary for additionally achieving fault tolerance. However, the challenge of making three-dimensional connectivity has limited cluster state generation capability up to two dimensions. Here we demonstrate the deterministic generation of a three-dimensional cluster state based on the photonic continuous-variable platform. To realize three-dimensional connectivity, we harness a crucial advantage of time–frequency modes of ultrafast quantum light: an arbitrary complex mode basis can be accessed directly, enabling connectivity as desired. We demonstrate the versatility of our method by generating cluster states with one-, two- and three-dimensional connectivities. For their complete characterization, we develop a quantum state tomography method for multimode Gaussian states. Moreover, we verify the cluster state generation by nullifier measurements as well as full inseparability tests. Our work paves the way towards fault-tolerant and universal-measurement-based quantum computing.
DOI: 10.1038/s41566-025-01631-2
Source: https://www.nature.com/articles/s41566-025-01631-2