Influence of Magnetic Field and LO Phonon Effect on Properties of Magnetopolarons and Qubit in Quantum Disks

Influence of external magnetic field, longitudinal-optical (LO) phonon effect and thickness of quantum disks (QDs) on the properties of electron-LO phonon strong-coupling magnetopolarons and the qubit is studied by using Lee -Low-Pines-Huybrechts variational method. The expressions for the mean number of phonons of magnetopolarons N̄\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\bar {N}$\end{document}, electron-LO phonon interaction energy Ee−ph, energies of the ground and first-excited states E0 and E1, oscillation period T0 of qubits and probability distribution ρ of electrons are derived. Results of numerical calculations show that the mean number of phonons of the ground state of magnetopolarons is larger than that of the first-excited state, the mean number of phonons of magnetopolarons N̄\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\bar {N}$\end{document} increases with increasing the cyclotron frequency ωc, confinement strength ω0 and coupling strength α, but decreases and oscillates with increasing the thickness of QDs L; Ee−ph is always negative, ∣Ee-ph∣ of the ground state is larger than that of the first-excited state, and ∣Ee-ph∣ increases with increasing ωc, ω0 and α but decreases with increasing L; E0 and E1 increase with increasing ωc, ω0 and α, but decrease with increasing L; T0 increases with increasing ω0 and L, but decreases with increasing α; ρ decreases and oscillates with increasing L, and decreases with increasing ω0; the variations of T0 and ρ with ωc and L are influenced by ω0 and α significantly.