Spin-charge separation and localization in one-dimension

TL;DR

This study investigates spin-charge separation and localization phenomena in one-dimensional quantum wires through tunneling experiments, revealing multiple modes, their velocities, and the effects of Coulomb interactions.

Contribution

It provides experimental measurements of multiple quantum modes and compares them with theoretical predictions, highlighting new insights into localization and mode behavior in 1D systems.

Findings

Observation of two spin modes and one charge mode

Mapping of mode velocities down to a critical density

Discrepancy between observed and predicted charge velocities

Abstract

We report on measurements of quantum many-body modes in ballistic wires and their dependence on Coulomb interactions, obtained from tunneling between two parallel wires in a GaAs/AlGaAs heterostructure while varying electron density. We observe two spin modes and one charge mode of the coupled wires, and map the dispersion velocities of the modes down to a critical density, at which spontaneous localization is observed. Theoretical calculations of the charge velocity agree well with the data, although they also predict an additional charge mode that is not observed. The measured spin velocity is found to be smaller than theoretically predicted.