Non-local interference and Hong-Ou-Mandel collisions of single Bogoliubov quasiparticles

TL;DR

This paper investigates the behavior of single Bogoliubov quasiparticles generated in a device with edge channels and superconducting regions, analyzing their interference and collision properties using single-electron sources to reveal their internal structure.

Contribution

It introduces a novel setup replacing voltage bias with single-electron sources to study Bogoliubov quasiparticle collisions and internal structure through zero-frequency noise measurements.

Findings

Demonstrates how to access the internal structure of Bogoliubov quasiparticles.

Shows that collisions with pure electrons reveal quasiparticle composition.

Provides a feasible experimental approach with superconductors.

Abstract

We consider a device which allows to create and probe single Majorana fermions, in the form of Bogoliubov quasiparticles. It is composed of two counter-propagating edge channels, each put in proximity with a superconducting region where Andreev reflection operates, and which thus converts electrons into Bogoliubov quasiparticles. The edge channels then meet at a quantum point contact where collisions can be achieved. A voltage biased version of the setup was studied in Phys. Rev. Lett. 112, 070604 (2014) and showed non-local interference phenomena and signatures of Bogoliubov quasiparticle collisions in the high frequency noise characteristics at the output, constituting an evidence of the Majorana fermion nature of these excitations. Here, voltage biased leads are replaced by single electron sources in order to achieve collisions of single Bogoliubov quasiparticles, with the major advantage that zero-frequency noise measurements are sufficient to access the intimate nature of Bogoliubov wave-packets. We compute the injection parameters of the source, and go on to investigate the Hanbury-Brown and Twiss and Hong-Ou-Mandel signal at the output, as a function of the mixing angle which controls the electron/hole component of the Bogoliubov wave-packet. In particular, information on the internal structure of the Bogoliubov quasiparticle can be recovered when such a quasiparticle collides with a pure electron. Experimental feasibility with singlet or triplet superconductors is discussed.