Non-equilibrium Majorana fluctuations

• Published in: New journal of physics Vol. 19; no. 6; pp. 63020 - 63029
• Main Author: Smirnov, Sergey
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 16.06.2017
• Subjects: 05.40.Ca; 71.10.Pm; 72.70.+m; Accessibility; effective charge; Electric currents; Equilibrium; Fermions; Majorana fermions; non-equilibrium noise; Physics; System effectiveness; Thermal noise; Variation
• ISSN: 1367-2630; 1367-2630
• DOI: 10.1088/1367-2630/aa70a9

Non-equilibrium physics of random events, or fluctuations, is a unique fingerprint of a given system. Here we demonstrate that in non-interacting systems with dynamics driven essentially by Majorana states the effective charge e * , characterizing the electric current fluctuations, is fractional. This is in contrast to non-interacting Dirac systems with the trivial electronic charge e * = e . In the Majorana state, however, we predict two different fractional effective charges at low and high energies, e l * = e 2 and e h * = 3 e 2 , accessible at low and high bias voltages, respectively. We show that while the low-energy effective charge e l * is sensitive to thermal fluctuations of the current, the high-energy effective charge e h * is robust against thermal noise. A unique fluctuation signature of Majorana fermions is therefore encoded in the high-voltage tails of the electric current noise easily accessible in experiments on strongly non-equilibrium systems even at high temperatures.