Electrical detection of the Majorana fusion rule for chiral edge vortices in a topological superconductor

Beenakker, C.W.J.; Grabsch, A.; Herasymenko, Y. (2019)

Article / Letter to editor

Majorana zero-modes bound to vortices in a topological superconductor have a non-Abelian exchange statistics expressed by a non-deterministic fusion rule: When two vortices merge they may or they may not produce an unpaired fermion with equal probability. Building on a recent proposal to inject edge vortices in a chiral mode by means of a Josephson junction, we show how the fusion rule manifests itself in an electrical measurement. A 2π2π phase shift at a pair of Josephson junctions creates a topological qubit in a state of even-even fermion parity, which is transformed by the chiral motion of the edge vortices into an equal-weight superposition of even-even and odd-odd fermion parity. Fusion of the edge vortices at a second pair of Josephson junctions results in a correlated charge transfer of zero or one electron per cycle, such that the current at each junction exhibits shot noise, but the difference of the currents is nearly noiseless.

• All authors: Beenakker, C.W.J.; Grabsch, A.; Herasymenko, Y.
• Date: 2019
• Journal: SciPost Physics
• Volume: 6
• Pages: 022