Effects of Electric Field and Temperature on RbCl Asymmetry Quantum Dot Qubit

Abstract

The effects of the electric field and temperature on a RbCl asymmetry quantum dot (AQD) qubit are investigated by using a variational method of the Pekar type. We first study the eigenenergies and eigenfunctions of the ground and first excited states of an electron strongly coupled to bulk longitudinal optical (LO) phonons with a three-dimensional (3D) harmonic potential under the influence of an electric field. This AQD two-level system may serve as a single qubit. We then obtain the time evolution of the electron's probability density when the electron is in the superposition state of the ground and first excited states. Finally, we investigate the effects of the electric field and temperature on the oscillating period, the time evolution of the electron's probability density and the coherence time. The numerical results show that the electron's probability density and its oscillatory period will increase (decrease) with increasing temperature in the low (high) temperature regime. The electron's probability density oscillates with a certain period in the AQD. The oscillating period is an increasing function of the temperature and the electric field. The coherence time is an increasing function of the temperature and the electric field, but it is a decreasing one of the transverse and longitudinal confinement strengths.