Document Type : Final File
Author
Department of Applied Physics, Faculty of Physics, University of Shahid Beheshti, Evin, Tehran, Islamic Republic of Iran
Abstract
We investigate the electronic transport through a single-level quantum-dot which is capacitively coupled to a charge-qubit. By employing the method of nonequilibrium Green's functions, we calculate the electric current through quantum dot at finite bias voltages. The Green's functions and self-energies of the system are calculated perturbatively and self-consistently to the second order of interaction between the quantum-dot and the charge-qubit by employing the Majorana fermion representation for isospin operators of the qubit. Our results show that in the particle-hole symmetric situation, the electric current of the QD exhibits a unitary linear conductance at low bias voltage and at the higher bias voltage it has a nonlinear dependence on the bias voltage. Moreover, we find that at some appropriate parameter regimes, the current through the QD as a function of gate voltage, at a fixed bias voltage shows bistability.
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