Eur. Phys. J. Special Topics 227, 1405–1411 (2018)
https://doi.org/10.1140/epjst/e2018-800034-5

Regular Article

Proposal for direct measuring of the Majorana number in a topological superconductor using a quantum dot

¹ School of Physics, Sun Yat-sen University, Guangzhou 510275, P.R. China
² Department of Physics, University of Texas at Austin, Austin, TX 78712, USA

^a e-mail: wangzh356@mail.sysu.edu.cn

Received: 30 March 2018
Received in final form: 28 July 2018
Published online: 4 October 2018

Abstract

We propose to directly measure the Majorana number for one-dimensional topological superconductors using a quantum dot. The setup consists of two topological superconducting wires with four Majorana zero modes, which are coupled to an external quantum dot. The measurement is achieved by utilizing the definition of the Majorana number, which is the charge-parity flipping when changing the boundary condition for the topological superconductor. We consider a control of the boundary condition with voltage gates. When the voltage on the gate are modulated sequentially, the boundary conditions changes and the parity of the superconducting state flips. We demonstrate that this parity flipping will change the electron occupation probability of the quantum dot, which reflects the value of the Majorana number.