College of Precision Instrument and Optoelectronics Engineering, Key Laboratory of Optoelectronics Information Technology of Ministry of Education, Tianjin University, Tianjin 300072, China.
Centre for Quantum Computation and Communication Technology, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 0200, Australia.
Phys Rev Lett. 2015 Mar 13;114(10):100403. doi: 10.1103/PhysRevLett.114.100403. Epub 2015 Mar 10.
The Einstein-Podolsky-Rosen (EPR) paradox, which was formulated to argue for the incompleteness of quantum mechanics, has since metamorphosed into a resource for quantum information. The EPR entanglement describes the strength of linear correlations between two objects in terms of a pair of conjugate observables in relation to the Heisenberg uncertainty limit. We propose that entanglement can be extended to include nonlinear correlations. We examine two driven harmonic oscillators that are coupled via third-order nonlinearity can exhibit quadraticlike nonlinear entanglement which, after a projective measurement on one of the oscillators, collapses the other into a cat state of tunable size.
爱因斯坦-波多尔斯基-罗森（Einstein-Podolsky-Rosen，EPR）佯谬最初被提出是为了论证量子力学的不完备性，后来演变成了量子信息的一种资源。EPR 纠缠描述了两个物体之间的线性相关性的强度，其通过一对共轭可观测量与海森堡不确定性限制相关联。我们提出纠缠可以扩展到包括非线性相关性。我们研究了两个通过三阶非线性耦合的受激谐振子，它们可以表现出二次非线性纠缠，这种纠缠在对其中一个谐振子进行投影测量后，会将另一个谐振子坍缩成可调节大小的猫态。
