Non-linear quantum effects in a triple quantum dot shuttle: hybrid entanglement properties

We study non-linear mechanical (Duffing quantum oscillating model) effects on the current and quantum correlations in a triple quantum dot shuttle system (TQDS), consisting of three linearly arranged quantum dots with an oscillating central dot. Quantum entanglement of the TQDS for the eigenstates is characterized by the Schmidt number (K) and is studied as a function of voltage difference across the system. A geometrical visualization representation of a three level charge subsystem (qutrit) is discussed and the cases with K larger than 2 are fully studied to provide a visual representation of the class of entangled charge-oscillation states in the model.