论文标题
截短量子状态的纠缠
Entanglement of truncated quantum states
论文作者
论文摘要
我们调查了希尔伯特空间截断对最初最大纠缠的$ m \ times m $二分化量子状态的纠缠的影响，此后在纠缠悬而未决的$ n \ times n \ times n $（$ n \ geq m $）统一后。截断 - 实际执行，例如，通过检测器的有限横截面 - 将状态投射到$ s \ times s $二维子空间（$ 3 \ leq s \ leq s \ leq n $）。对于随机的本地统一进化，我们获得了一个简单的分析公式，该公式表达截断引起的纠缠损失，这是$ n $，$ m $和$ s $的函数。
We investigate the impact of Hilbert-space truncation upon the entanglement of an initially maximally entangled $m\times m$ bipartite quantum state, after propagation under an entanglement-preserving $n \times n$ ($n\geq m$) unitary. Truncation -- physically enforced, e.g., by a detector's finite cross section -- projects the state onto an $s \times s$-dimensional subspace ($3\leq s \leq n$). For a random local unitary evolution, we obtain a simple analytical formula that expresses the truncation-induced entanglement loss as a function of $n$, $m$ and $s$.
