Ekert Artur K, Alves Carolina Moura, Oi Daniel K L, Horodecki Michał, Horodecki Paweł, Kwek L C
Centre for Quantum Computation, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.
Phys Rev Lett. 2002 May 27;88(21):217901. doi: 10.1103/PhysRevLett.88.217901. Epub 2002 May 13.
We present a simple quantum network, based on the controlled-SWAP gate, that can extract certain properties of quantum states without recourse to quantum tomography. It can be used as a basic building block for direct quantum estimations of both linear and nonlinear functionals of any density operator. The network has many potential applications ranging from purity tests and eigenvalue estimations to direct characterization of some properties of quantum channels. Experimental realizations of the proposed network are within the reach of quantum technology that is currently being developed.
我们提出了一种基于受控交换门的简单量子网络，该网络无需借助量子层析成像就能提取量子态的某些特性。它可用作直接量子估计任意密度算符的线性和非线性泛函的基本构建模块。该网络有许多潜在应用，从纯度测试、本征值估计到量子信道某些特性的直接表征。所提出网络的实验实现目前正在发展的量子技术范围内。
