Coherent control of double-dot molecules using Aharonov-Bohm magnetic flux

Bonding and antibonding states of artificial molecules have been realized in experiments by directly coupling two quantum dots. Without a direct coupling between two nearby quantum dots, here we show that under a very unusual condition (i.e., a large asymmetrical couplings to the leads at a large bias) continuous coherence control of double-dot charge states can be achieved by changing the flux through a double-quantum-dot Aharonov-Bohm (AB) interferometer. Using magnetic flux to control double-dot molecular-state coherence is very robust against charge noise. We explicitly present the flux-dependent real-time processes of molecular-state formation. In contrast with the transport current, which has a 2π period, the quantum state of the double-quantum-dot molecule has a 4π period in the AB flux.