Anomalous spin-charge separation in a driven Hubbard system

TL;DR

This paper explores how periodic driving can manipulate spin-charge separation in Hubbard systems, revealing regimes where charge slows down or becomes frozen, with distinct behaviors in one and two dimensions.

Contribution

It introduces a novel method to control spin-charge separation using periodic driving, including analytical predictions and numerical validation in low-dimensional systems.

Findings

In 1D, charge can become slower than spin or frozen.

In 2D, driving slows both charge and spin, causing complex interference effects.

Abstract

Spin-charge separation (SCS) is a striking manifestation of strong correlations in low-dimensional quantum systems, whereby a fermion splits into separate spin and charge excitations that travel at different speeds. Here, we demonstrate that periodic driving enables control over SCS in a Hubbard system near half-filling. In one dimension, we predict analytically an exotic regime where charge travels slower than spin and can even become 'frozen', in agreement with numerical calculations. In two dimensions, the driving slows both charge and spin, and leads to complex interferences between single-particle and pair-hopping processes.