Jing Jietai, Zhang Jing, Yan Ying, Zhao Fagang, Xie Changde, Peng Kunchi
The State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan, 030006, People's Republic of China.
Phys Rev Lett. 2003 Apr 25;90(16):167903. doi: 10.1103/PhysRevLett.90.167903. Epub 2003 Apr 23.
A tripartite entangled state of bright optical field is experimentally produced using an Einstein-Podolsky-Rosen entangled state for continuous variables and linear optics. The controlled dense coding among a sender, a receiver, and a controller is demonstrated by exploiting the tripartite entanglement. The obtained three-mode "position" correlation and relative "momentum" correlation between the sender and the receiver, and thus the improvements of the measured signal to noise ratios of amplitude and phase signals with respect to the shot noise limit are 3.28 and 3.18 dB, respectively. If the mean photon number n equals 11 the channel capacity can be controllably inverted between 2.91 and 3.14. When n is larger than 1.0 and 10.52, the channel capacity of the controlled dense coding is predicted to exceed the ideal single channel capacity of coherent and squeezed state light communication, respectively.
利用连续变量的爱因斯坦-波多尔斯基-罗森纠缠态和线性光学，通过实验产生了明亮光场的三方纠缠态。利用三方纠缠演示了发送方、接收方和控制器之间的受控密集编码。在发送方和接收方之间获得的三模“位置”相关性和相对“动量”相关性，以及因此幅度和相位信号相对于散粒噪声极限的测量信噪比的提高分别为3.28 dB和3.18 dB。如果平均光子数n等于11，则信道容量可以在2.91和3.14之间可控地反转。当n大于1.0和10.52时，预计受控密集编码的信道容量将分别超过相干态和压缩态光通信的理想单信道容量。
