Universal continuous-variable quantum computation: Requirement of optical nonlinearity for photon counting

作     者：Stephen D. Bartlett Barry C. Sanders 

作者机构：Department of Physics and Centre for Advanced Computing–Algorithms and Cryptography Macquarie University Sydney New South Wales 2109 Australia Quantum Entanglement Project ICORP JST Edward L. Ginzton Laboratory Stanford University California 94305-4085 

出 版 物：《Physical Review A》 (Phys Rev A)

年 卷 期：2002年第65卷第4期

页      面：042304-042304页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

主　　题：Quantum optics 

摘      要：Although universal continuous-variable quantum computation cannot be achieved via linear optics (including squeezing), homodyne detection, and feed-forward, inclusion of ideal photon-counting measurements overcomes this obstacle. These measurements are sometimes described by arrays of beam splitters to distribute the photons across several modes. We show that such a scheme cannot be used to implement ideal photon counting and that such measurements necessarily involve nonlinear evolution. However, this requirement of nonlinearity can be moved “off-line, thereby permitting universal continuous-variable quantum computation with linear optics.