J-C模型腔场谱与光场量子比特的探测

Cavity Field Spectrum of Jaynes-Cummings Model and Measurement of Field Qubit

研究了Jaynes-Cummings模型的腔场谱的量子特性。利用数值计算结果,绘出了初始光场处于| 0〉,| 1〉光子数态叠加态时的光谱结构。讨论了光谱结构与初始场量子比特之间的联系。研究结果表明,Jaynes-Cummings模型腔场谱结构特征能够反映量子比特中几率幅的变化,且二者存在一一对应关系,因此可以用光谱结构测定量子比特几率幅的数值;但是,从腔场谱结构特征中不能获取量子相位的信息,不能探测量子比特相位的数值。这反映出用腔场谱对光场量子比特探测的有效性和局限性。

The cavity field spectrum of the Jaynes-Cummings model is investigated.The results for the initial fields in superposition state of zero and one photon Fork states（a qubit of cavity field） are presented.The relation of the spectral structure and the initial field qubit is analyzed.The result shows that the influence of probability amplitude of the initial field qubit on the spectral structure is sensitive with one-to-one correspondence between them.No information about the quantum phase of the qubit can be gained from the cavity field spectrum.