MIMO量子信道的空间自由度研究

量子通信是一个量子密钥分发过程，目前采用的通信技术严重制约了量子密钥分发的比特率.将多输入多输出（MIMO）技术应用于量子通信系统，提高量子密钥分发的比特率,促进量子通信向高速大容量发展.然而，量子场本身不可避免地存在量子噪声约束容量的增长，限制了可利用空间资源，即空间自由度.文中采用光子场的量子化和满足Schrdinger方程条件的电磁场波动方程推导出MIMO量子信道的空间自由度上限，为开发稳健的MIMO量子通信空时处理算法和优化设计高性能MIMO量子通信系统提供理论基础和技术支持. 关键词： 多输入多输出 量子密钥分发 Schrdinger方程 光子场的量子化

The spatial degrees of freedom of MIMO quantum channels

Quantum communication is a process of quantum key distribution （QKD）. Current QKD technology restricts communication to a low bit rate. To improve the QKD bit rate and develop high rate and capacity, we propose a multiple-input-multiple-output quantum key distribution system. However, quantum field itself inevitably involves quantum noise （which is determined by the quantum mechanics ）, which restrains the increase of capacity, and limits space resource utilization, that is, the problem of spatial degrees of freedom arises. The quantumization of the photon field and the electromagnetic wave equation satisfying the Schrdinger equation condition are adopted to investigate the upper bound of the spatial degrees of freedom for MIMO quantum channels, which will provide theoretical support and technical basis for developing robust space time processing algorithm for MIMO quantum communication and designing high performance systems.