Matsukevich D N, Chanelière T, Bhattacharya M, Lan S-Y, Jenkins S D, Kennedy T A B, Kuzmich A
School of Physics, Georgia Institute of Technology, Atlanta, 30332-0430, USA.
Phys Rev Lett. 2005 Jul 22;95(4):040405. doi: 10.1103/PhysRevLett.95.040405.
We describe a new experimental approach to probabilistic atom-photon (signal) entanglement. Two qubit states are encoded as orthogonal collective spin excitations of an unpolarized atomic ensemble. After a programmable delay, the atomic excitation is converted into a photon (idler). Polarization states of both the signal and the idler are recorded and are found to be in violation of the Bell inequality. Atomic coherence times exceeding several microseconds are achieved by switching off all the trapping fields--including the quadrupole magnetic field of the magneto-optical trap--and zeroing out the residual ambient magnetic field.
我们描述了一种用于概率性原子 - 光子（信号）纠缠的新实验方法。两个量子比特态被编码为非极化原子系综的正交集体自旋激发。经过可编程延迟后，原子激发被转换为一个光子（闲频光）。信号光和闲频光的偏振态都被记录下来，并且发现它们违反了贝尔不等式。通过关闭所有捕获场——包括磁光阱的四极磁场——并消除残余的环境磁场，实现了超过几微秒的原子相干时间。
