近日，美国杜克大学的Boyu Gao&Natalie Klco及其研究团队取得一项新进展。经过不懈努力，他们对多体高斯量子系统中部分转置导引的纠缠类和最小噪声滤波进行研究。相关研究成果已于2024年6月11日在国际知名学术期刊《物理评论A》上发表。

在经典噪声的影响下，量子关联性的降低和失真使得纠缠作为量子信息处理协议中资源的可用性出现不同程度的降低。尽管在一般情况下，最小化混合量子态所需的纠缠量仍是一项挑战，但本文成功识别了一类特殊的多体高斯量子态（表示为N IC），它们拥有与纯态类似的双模二体纠缠结构。

值得注意的是，这类量子态的对数负纠缠测度在包含经典关联后依然保持不变，从而能够清晰地量化出最佳的纠缠资源。此外，这一特殊的子类被发现嵌入在更广泛的多体高斯态（N-SOL）之中，这些高斯态在检测过程中依然保持着双模纠缠结构。

从标量场真空到捕获离子链的局部轴向运动模式，这两类纠缠在理论和实验应用中都是相关的。为了准确识别这些纠缠结构中的成员，利用响应部分转置时预示的不可分子空间来设计最小噪声滤波过程是必要的、充分的且可计算的。将此过程应用于自由标量场真空的类空间区域，能够提升资源上界，为局部探测器阵列观测到的量子场的量子模拟所需的纠缠提供新的深刻见解。

附：英文原文

Title: Partial-transpose-guided entanglement classes and minimum noise filtering in many-body Gaussian quantum systems

Author: Boyu Gao, Natalie Klco

Issue&Volume: 2024/06/11

Abstract: The reduction and distortion of quantum correlations in the presence of classical noise leads to varied levels of inefficiency in the availability of entanglement as a resource for quantum information processing protocols. While generically minimizing required entanglement for mixed quantum states remains challenging, a class of many-body Gaussian quantum states (denoted N IC) is here identified that exhibits two-mode bipartite entanglement structure, resembling that of pure states, for which the logarithmic negativity entanglement measure remains invariant upon inclusion of the classical correlations and optimal entanglement resources can be clearly quantified. This subclass is found to be embedded within a broader class of many-body Gaussian states (denoted N-SOL) that retain two-mode entanglement structure for detection processes. These two entanglement classes are relevant in theoretical and experimental applications from the scalar field vacuum to the local axial motional modes of trapped ion chains. Utilizing the subspace that heralds inseparability in response to partial transposition, a minimum noise filtering process is designed to be necessary, sufficient, and computable for determining membership in these classes of entanglement structure. Application of this process to spacelike regions of the free scalar field vacuum is found to improve resource upper bounds, providing new understanding of the entanglement required for the quantum simulation of quantum fields as observed by arrays of local detectors.

DOI: 10.1103/PhysRevA.109.062413

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.109.062413