Noninvasive detection of the evolution of the charge states of a double dot system

Coupled quantum dots are potential candidates for qubit systems in quantum computing. We use a noninvasive voltage probe to study the evolution of a coupled dot system from a situation where the dots are coupled to the leads to a situation where they are isolated from the leads. Our measurements allow us to identify the movement of electrons between the dots and we can also identify the presence of a charge trap in our system by detecting the movement of electrons between the dots and the charge trap. The data also reveal evidence of electrons moving between the dots via excited states of either the single dots or the double dot molecule.