Many-body dispersions in interacting ballistic quantum wires

TL;DR

This study investigates the collective excitation spectrum of interacting electrons in one-dimensional quantum wires, revealing significant effects of Coulomb interactions, finite size, and spin-charge separation through conductance measurements.

Contribution

It provides experimental evidence of many-body dispersions and spin-charge separation in ballistic quantum wires, highlighting deviations from non-interacting models.

Findings

30% enhancement of excitation velocity due to interactions

Observation of finite size effects in short wires

Manifestation of spin-charge separation via moire patterns

Abstract

We have measured the collective excitation spectrum of interacting electrons in one-dimension. The experiment consists of controlling the energy and momentum of electrons tunneling between two clean and closely situated, parallel quantum wires in a GaAs/AlGaAs heterostructure while measuring the resulting conductance. We measure excitation spectra that clearly deviate from the non-interacting spectrum, attesting to the importance of Coulomb interactions. Notable is an observed 30% enhancement of the velocity of the main excitation branch relative to non-interacting electrons with the same density. In short wires, finite size effects resulting from broken translational invariance are observed. Spin - charge separation is manifested through moire patterns, reflecting different spin and charge excitation velocities.