Realization of a Nonlocal Persistent Current Qubit with the Help of Majorana Bound States

We investigate the persistent currents in one coupled quantum-ring structure in which each ring is formed by the couplings between one of the Majorana bound states and the end dots of a quantum dot chain. It is found that even in the case of Majorana zero mode, the persistent current in one ring can be efficiently manipulated by tuning the magnetic flux in the other ring if the two rings both possess the odd quantum dots. This means that the Majorana bound states can assist to realize the coherent nonlocal manipulation of the persistent currents. Accordingly, a nonlocal persistent current qubit can be achieved with the help of Majorana bound states. However, if even quantum dots exist in one ring, the nonlocal control of the persistent currents will vanish and the qubit cannot be realized. By performing the representation transformation, we present a detailed explanation about the odd-even effect of the persistent current.