量子比特的密度矩阵表示

Representation of Density Matrix in Quantum bit

介绍了量子比特、密度矩阵和Bloch向量的概念,然后借助外积这一数学工具给出了单量子比特和混合态量子比特的密度矩阵表示及其相关性质,以矩阵及算子理论为基础,对纯态、混合态、缠绕态及叠加态的密度矩阵表示进行了分析,所得结果有助于加深理解量子理论。

At first, the concept of quantum bit, the density matrix and Bloch vector were introduced. Then by using the outer product mathematical tools, the density matrix of single quantum bit, the mixed state quantum bit and the related properties were discussed. Based on the matrix operator theory, the pure states, mixed states; entangle state, the superposition states and the density matrix were analysed. The researching results contributed to the deep understanding of quantum theory.