Shannon entropy and decoherence of bound magnetopolaron in a modified cylindrical quantum dot

Abstract

In this paper, we calculate the time evolution of the quantum mechanical state of a bound magnetopolaron in a modified cylindrical quantum dot. In the condition of strong coupling, we investigate the eigen energies and the eigenfunctions of the ground state and the first excited state, respectively. This system may be employed as a two-level quantum system qubit and therefore be helpful for storage of information. The Shannon entropy is used to investigate the decoherence of the qubit when the latter is in the superposition state of the ground and the first excited states. We also study the influence of the electric field, the magnetic field and the Coulomb potential on the decoherence time, eigen energies of the ground state, and the first excited state. It is shown that, the phonon spontaneous emission causes the decoherence of the qubit. We plot the decay of the density matrix of the qubit and the coherent term of the density matrix element [Formula: see text] (or [Formula: see text]) in a function of time for different coupling strengths, confinement lengths and dispersion coefficient.