Conductance of a quantum dot with a Hubbard interaction in the presence of a boson field

We theoretically study the conductance of a quantum dot on which there is an on-site Coulomb interaction of energy U as well as a boson-electron interaction of coupling constant g. The independent boson model is used to describe the boson field. The conductance is calculated via a Landauer-type formula by the equations-of-motion method of the retarded Green’s function. An analytic and compact formula for the retarded Green’s function is obtained with two effective self-energies which are renormalized by both electron-electron and boson-electron interactions. Our numerical results show that the presence of a boson field typically leads to sideband peaks and decreases the main peak related to the Coulomb interaction. The sideband peak height is sensitive to boson-electron interaction coupling constant g. We also present the temperature dependence of the conductance in the presence of a boson field.