Majorana tunneling in a one-dimensional wire with non-Hermitian double quantum dots

Abstract

The combination of non-Hermitian physics and Majorana fermions can give rise to new effects in quantum transport systems. In this work, we investigate the interplay of PT-symmetric complex potentials, Majorana tunneling and inter-dot tunneling in a nonHermitian double quantum dot system. It is found that in weak-coupling regime the Majorana tunneling take pronounced effects to the transport properties of such a system, manifested as splitting the unitary peak into three and a reduced 1/4 peak in transmission function. In the presence of the PT-symmetric complex potentials and inter-dot tunneling, the 1/4 central peak is robust against them, while the two side peaks are tuned by them. The interdot tunneling only induces asymmetry, instead of moving the conductance peak, due to the robustness of Majorana modes. There is an exceptional point induced by the union of Majorana tunneling and inter-dot tunneling. With increased PT-symmetric complex potentials, the two side peaks will move towards each other. When the exceptional point is passed through, these two side peaks will disappear. In strong-coupling regime, Majorana Fermion induces a 1/4 conductance dip instead of the three-peak structure. PT-symmetric complex potentials induce two conductance dips pinned at exceptional point. These effects should be accessible in experiment.