Coulomb blockade of chiral Majorana and complex fermions far from equilibrium

Abstract

We study charge transport in a single-electron transistor implemented as an interferometer such that the Coulomb-blockaded middle island contains a circular chiral Majorana or Dirac edge mode. We concentrate on the regime of small conductance and provide an asymptotic solution in the limit of high transport voltage exceeding the charging energy. The solution is achieved using an instantonlike technique. The distinctions between Majorana and Dirac cases appear when the tunnel junctions are unequal. The main difference is in the offset current at high voltages which can be higher, up to 50% in the Majorana case. It is caused by an additional particle-hole symmetry of the distribution function of Majorana fermions. There is also an eye-catching distinction between the oscillation patterns of the current as a function of the gate charge. We conjecture this distinction survives at lower transport voltages as well.