Transient dynamics of spin-polarized injection in helical Luttinger liquids

TL;DR

This paper investigates the transient behavior of spin-polarized electrons in helical Luttinger liquids, revealing fractionalization effects during time evolution that are not observable in steady-state measurements.

Contribution

It demonstrates that signatures of charge and spin fractionalization appear in the transient dynamics of helical Luttinger liquids, despite the absence of such evidence in dc measurements.

Findings

Transient dynamics reveal fractionalization signatures.

No fractionalization evidence in dc measurements.

Helical Luttinger liquid behavior emerges in time evolution.

Abstract

We analyze the time evolution of spin-polarized electron wave packets injected into the edge states of a two-dimensional topological insulator. In the presence of electron interactions, the system is described as a helical Luttinger liquid and injected electrons fractionalize. However, because of the presence of metallic detectors, no evidences of fractionalization are encoded in dc measurements, and in this regime the system do not show deviations from its non-interacting behavior. Nevertheless, we show that the helical Luttinger liquid nature emerges in the transient dynamics, where signatures of charge/spin fractionalization can be clearly identified.