Half-integer charge injection by a Josephson junction without excess noise

Abstract

A Josephson junction in a topological superconductor can inject a charge e/2 into a normal-metal contact, carried by chiral Majorana edge modes. Here we address the question whether this half-integer charge is a sharp observable, without quantum fluctuations. Because the Majorana modes are gapless, they support charge fluctuations in equilibrium at zero temperature. But we find that the excess noise introduced out of equilibrium by the e/2 charge transfer vanishes. We discuss a strategy to reduce the equilibrium fluctuations, by means of a heavy-tailed time-dependent detection efficiency, to achieve a nearly noiseless half-integer charge transfer.

11 pages, 4 figures; V2: added an appendix on the alternative calculation via bosonisation

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Cited by in corpus (8)

• Opportunities in topological insulator devices
• Current-induced breakdown of the quantum anomalous Hall effect
• Shot noise distinguishes Majorana fermions from vortices injected in the edge mode of a chiral p-wave superconductor
• Microwave response of a chiral Majorana interferometer
• Auto- versus cross-correlation noise
• Non-Abelian anyon statistics through AC conductance of a Majorana interferometer
• Dynamical simulation of the injection of vortices into a Majorana edge mode
• Coulomb blockade of chiral Majorana and complex fermions far from equilibrium