论文标题
通过计数和定位纠缠测量值来纠缠净化和定位错误
Entanglement purification by counting and locating errors with entangling measurements
论文作者
论文摘要
我们考虑符号状态多个副本的纠缠净化协议。我们使用高维辅助系统以明确和控制的方式来了解嘈杂合奏中错误的数字和位置,从而减少合奏中的噪声量并净化其余状态。这使我们能够为任何数量的副本设计纠缠净化协议,这些副本特别适合少数预期错误,即初始状态的高保真度。主要工具是一个计数门,可以将所需的非本地信息传输到高维纠缠的辅助状态中。我们将我们的方案与基于成对的副本运行的标准复发方案以及在(渐近)大量副本上运行的哈希和繁殖方案进行了比较。我们的协议在这两个制度之间插值,导致更高的忠诚度和产量。我们说明了我们对二手量子态状态的方法,并将其推广以净化多方GHz状态。
We consider entanglement purification protocols for multiple copies of qubit states. We use high-dimensional auxiliary entangled systems to learn about number and positions of errors in the noisy ensemble in an explicit and controlled way, thereby reducing the amount of noise in the ensemble and purifying the remaining states. This allows us to design entanglement purification protocols for any number of copies that work particularly well for a small number of expected errors, i.e. high fidelity of initial states. The main tool is a counter gate with which the required non-local information can be transferred into the high-dimensional entangled qudit auxiliary states. We compare our schemes to standard recurrence protocols that operate on pairs of copies, and hashing and breeding protocols that operate on a (asymptotically) large number of copies. Our protocols interpolate between these two regimes, leading to a higher achievable fidelity and yield. We illustrate our approach for bipartite qubit states, and generalize it to purify multi-party GHZ states.