Simon Christoph, Irvine William T M
Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.
Phys Rev Lett. 2003 Sep 12;91(11):110405. doi: 10.1103/PhysRevLett.91.110405.
Two trapped ions that are kilometers apart can be entangled by the joint detection of two photons, each coming from one of the ions, in a basis of entangled states. Such a detection is possible with linear optical elements. The use of two-photon interference allows entanglement distribution free of interferometric sensitivity to the path length of the photons. The present method of creating entangled ions also opens up the possibility of a loophole-free test of Bell's inequalities.
相距数公里的两个俘获离子可以通过在纠缠态基下对两个光子（每个光子分别来自一个离子）的联合探测而实现纠缠。使用线性光学元件就可以进行这样的探测。双光子干涉的运用使得纠缠分布不受光子路径长度的干涉测量灵敏度的影响。目前创建纠缠离子的方法也为无漏洞检验贝尔不等式开辟了可能性。
