Interactions of Fano resonances in the transmission for an Aharonov-Bohm ring with two embedded quantum dots are examined. As the interaction parameter between two quantum dots is modulated, two Fano dipoles a resonance zero-pole pair in the complex-energy plane form a quasiparticle, which behaves as a coupled object called a “Fano quadrupole.” In the strong overlapping regime of Fano resonance, the collision and merging of resonance zeros take place and these zeros move off from the real axis of energy in complex conjugate pairs. The periodic motion of both transmission zeros and resonance poles as a function of a magnetic field is discussed.

Date of this Version

September 2005