Selecting the asymmetric Gaussian (AG) potential to describe the confinement of electron in a disk-shaped quantum dot (QD), the ground state and the first excited state energy and wave function of the system are derived by using the Lee $$\hbox {--}$$ -- Low $$\hbox {--}$$ -- Pines (LLP) Pekar transformation variational method, and the two-level structure required for a qubit is constructed. The influence of material parameters such as the dispersion coefficient, dielectric constant ratio and electron $$\hbox {--}$$ -- phonon coupling constant on the qubit properties of AG potential QD with the electromagnetic field are investigated. The results show that the electric field and magnetic field have opposite adjustment functions for the formation of qubit. The electric field is advantageous for the qubit survival and information storage, while magnetic field and electron $$\hbox {--}$$ -- phonon coupling are detrimental to the qubit survival and information storage, respectively. The decoherence time of the qubit increases with increasing magnetic field cyclotron frequency ‘from the turning point’. Applying an electric field, increasing the dielectric constant ratio, the dispersion coefficient and the electron $$\hbox {--}$$ -- phonon coupling constant of the materials are all beneficial to improve the coherence of the qubit.

中文翻译：

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色散系数和介电常数比对带电磁场的非对称高斯势量子点量子比特的影响

选择非对称高斯 (AG) 势来描述圆盘状量子点 (QD) 中电子的约束，使用 Lee $$\hbox 推导出系统的基态和第一激发态能量和波函数{--}$$ -- Low $$\hbox {--}$$ -- Pines (LLP) Pekar变换变分方法，构建了一个qubit所需的二级结构。研究了色散系数、介电常数比和电子$$\hbox {--}$$--声子耦合常数等材料参数对电磁场下AG势QD量子比特性质的影响。结果表明，电场和磁场对量子比特的形成具有相反的调节作用。电场有利于量子比特的生存和信息存储，而磁场和电子 $$\hbox {--}$$ -- 声子耦合分别对量子位生存和信息存储有害。量子位的退相干时间随着“从转折点”开始增加磁场回旋频率而增加。施加电场、增大介电常数比、色散系数和电子$$\hbox {--}$$ -- 材料的声子耦合常数都有利于提高量子比特的相干性。