Impurity Effect of Asymmetric Gaussian Potential Quantum Well Qubit

Abstract

On the condition of strong electron-LO phonon coupling in an asymmetrical Gaussian potential quantum well (AGPQW) with a hydrogen-like impurity at the origin of the coordinate, we calculate the eigenenergies and the eigenfunctions of the ground and the first excited states (GFES) by using a variational method of Pekar type. A single qubit can be realized in this two-level quantum system. We calculate the time evolution and the change of the coordinate of the electron’s probability density. When the electron is in the superposition state of the GFES, the electron’s probability density oscillates in the AGPQW with a certain period \(T_0 =20.716\) fs. It turns out that due to the presence of the asymmetrical Gaussian potential in the growth direction of the QW, the electron probability density shows a single peak configuration in the coordinate range of \(z>0\), whereas it equals to zero in the range of \(z 0.24\) nm. It has a minimum when \(R=0.24\) nm.