Phase Evolution of an Aharonov–Bohm Ring with an Embedded Quantum Dot

We demonstrate there are two phase shifts, which a quantum dot caused, in a modified Aharonov–Bohm (AB) ring. On two sides of the conductance resonance peaks the AB oscillations have different functional forms as a function of the bias voltage on the QD, that is similar to the recent experiment. We find that several special incident energies of electrons may drive the AB ring system into a resonant state (T=1) or antiresonant state (T=0), respectively.