Nonlocality and dynamic response of Majorana states in fermionic superfluids

I M Khaymovich,A S Melnikov,J P Pekola

doi:10.1088/1367-2630/aa983d

Abstract

We suggest a microscopic model describing the nonlocal ac response of a pair of Majorana states in fermionic superfluids beyond the tunneling approximation. The time-dependent perturbations of quasiparticle transport are shown to excite finite period beating of the wavefunction between the distant Majorana states. We propose an experimental test to measure the characteristic time scales of quasiparticle transport through the pair of Majorana states defining, thus, quantitative characteristics of nonlocality known to be a generic feature of Majorana particles.

Highlights

Search for Majorana bound states (MBS) has recently become an active topic in the condensed matter community [1,2,3]
In the present manuscript we show that the previous studies of the nonlocality in the system of the MBS suffer from another key omission, namely they do not take into account the nonequilibrium effects responsible for the mixing of the quasiparticle eigenfunctions with the positive and negative energies in the dynamic processes
We proceed with the analysis of the dynamic response of a pair of Majorana partners and consider two generic examples of the time-dependent transport realized by the modulating tunnel barrier: (i) the phase-shifted sinusoidal driving with GL(t ) = G0 probe driving by Dt -broadened delta-functional i.e., with Gk(t ) = Gk0dDt (t ) + Gkt dDt (t - t)

Summary

Introduction

Search for Majorana bound states (MBS) has recently become an active topic in the condensed matter community [1,2,3]. These exotic states are known to be characterized by the coinciding annihilation and creation operators. This is why it is quite natural to look for such states in superconducting systems where the order parameter Δ is known to mix particles (electrons) and anti-particles (holes) because of the Andreev scattering processes. Despite the clear and reliable observation of zero bias peaks (ZBP) in the differential conductance measurements [8, 9] and on the change in the charge periodicity of conductance in Coulomb blockade regime [10] consistent with the existence of MBS it would be extremely important to probe other attributes of these states especially keeping in mind alternative explanations of the ZBP based on Kondo physics [11]

Objectives

Results

Conclusion