量子环中量子比特的声子效应

在量子环中电子与体纵光学声子强耦合的情况下，通过求解能量本征方程，得出了电子的基态和第一激发态的本征能量及其波函数，进而以电子-声子系的基态与第一激发态构造了一个量子比特.数值计算结果表明量子比特内电子的空间概率密度分布随时间和空间角坐标作周期性振荡，且振荡周期随耦合强度的增大而减小，说明声子将导致量子比特相干性降低；还表明振荡周期随量子环内径（或外径）的增大而增大，因此适当改变量子环的尺度，可以提高量子比特的相干性.关键词：量子环量子信息量子比特

The phonon effect of qubit in quantum ring

Under the condition of electron-LO photon strong coupling, the eigenfunction and the eigenenergy of the ground state and the first excited state of the electron in quantum ring, are obtained by solving precisely the Schrdinger equation. A qubit is formed by overlaying both the ground state and the first excited state of the electron-LO phonon system.Numerical calculations indicate that the distribution of the probability density of electrons in quantum oscillates periodically with time and angle coordinate. The oscillating period decreases with the increase of the electron-LO phonon coupling strength, which shows that the existence of phonon can reduce the coherence of qubit, and that the oscillating period increases with the increasing inner（or outer） radius of quantum ring. Therefore, the coherence of qubit can be improved by choosing proper size of quantum ring.