论文标题
使用被动操作的分离跨阶段相关性
Decoupling Cross-Quadrature Correlations using Passive Operations
论文作者
论文摘要
高斯量子状态的子系统之间的正交相关性完全以其协方差矩阵为特征。例如，协方差矩阵确定国家的纠缠或反折叠量。在这里，我们确定何时仅使用被动操作来删除共轭二次的相关性。这种相关通常是不需要的，并且由于实验性跨二元污染而产生。使用Autonne-takagi分解，我们提出了必要和足够的条件，以确定何时可以去除这种情况。我们的证明是建设性的，只要有可能，我们就会获得所需的被动操作的明确表达。
Quadrature correlations between subsystems of a Gaussian quantum state are fully characterised by its covariance matrix. For example, the covariance matrix determines the amount of entanglement or decoherence of the state. Here, we establish when it is possible to remove correlations between conjugate quadratures using only passive operations. Such correlations are usually undesired and arise due to experimental cross-quadrature contamination. Using the Autonne--Takagi factorisation, we present necessary and sufficient conditions to determine when such removal is possible. Our proof is constructive, and whenever it is possible we obtain an explicit expression for the required passive operation.
