The effect of intrinsic decoherence on quantum dynamics of two coupled double quantum dot systems

Abstract

Double quantum dot (DQD) system is an ideal candidate for qubit in quantum information theory. Hence, we will investigate the two couple DQDs in the presence of intrinsic decoherence. We derive the energy spectrum and the corresponding eigenstates. Using the concurrence as a measure of entanglement for a bipartite pure state, the entanglement of the energy eigenstates is obtained and shows that the energy eigenstates reduce to the Bell states for Δ1=Δ2=0. The effects of the physical parameters such as tunneling rate between two QDs, Coulomb coupling, and intrinsic decoherence on the entanglement and the dynamics of DQD system will be examined. Furthermore, fidelity is used to measure how close the dynamically evolved state is to the initial state. It is found that for a given Γ and the smaller (larger) values of Δ2 (coulomb potential), the DQD system is more robust to the destructive effect of the intrinsic decoherence.