Hong-Ou-Mandel experiment for temporal investigation of single electron fractionalization

TL;DR

This paper investigates how Coulomb interactions cause single electrons to fractionalize into collective modes in a quantum Hall conductor, using a Hong-Ou-Mandel experiment to observe the process in real time.

Contribution

It demonstrates the use of two-particle interference to directly observe electron fractionalization and collective excitations in a quantum Hall system.

Findings

Electron fractionalization observed in time domain.

Interaction-induced collective modes identified.

Single-electron quasiparticle destruction confirmed.

Abstract

Coulomb interaction has a striking effect on electronic propagation in one dimensional conductors. The interaction of an elementary excitation with neighboring conductors favors the emergence of collective modes which eventually leads to the destruction of the Landau quasiparticle. In this process, an injected electron tends to fractionalize into separated pulses carrying a fraction of the electron charge. Here we use two-particle interferences in the electronic analog of the Hong-Ou-Mandel experiment in a quantum Hall conductor at filling factor 2 to probe the fate of a single electron emitted in the outer edge channel and interacting with the inner one. By studying both channels, we analyze the propagation of the single electron and the generation of interaction induced collective excitations in the inner channel. These complementary information reveal the fractionalization process in time domain and establish its relevance for the destruction of the quasiparticle which degrades into the collective modes.