Persistent Current in a Mesoscopic Ring Side-Attached with a Quantum Dot

We theoretically investigate properties of the ground state of a closed dot-ring system with a magnetic flux in the Kondo regime by means of a tight-banding Anderson Hamiltonian, using the Slave--Boson mean-field approach. The persistent current shows interesting dependences on the parity and on the size of the system. The signature of Kondo resonance at xi_k/L=0.15 is expected to be observed experimentally in the future. With the intensity of the coupling t_D changes from weak to strong, the properties of the system changes largely, which are different from the in-line one because of the attached dot.