Optical Nondestructive Controlled-NOT Gate without Using Entangled   Photons
  We present and experimentally demonstrate a novel optical nondestructive controlled-NOT gate without using entangled ancilla. With much fewer measurements compared with quantum process tomography, we get a good estimation of the gate fidelity. The result shows a great improvement compared with previous experiments. Moreover, we also show that quantum parallelism is achieved in our gate and the performance of the gate can not be reproduced by local operations and classical communications. 
Xiao-Hui Bao, Teng-Yun Chen, Qiang Zhang, Jian Yang, Han Zhang, Tao   Yang, and Jian-Wei Pan