Stability of Floquet sidebands and quantum coherence in 1D strongly interacting spinless fermions

TL;DR

This study explores how electron interactions and perturbations affect the stability of Floquet-Bloch sidebands in 1D strongly interacting spinless fermions, revealing conditions for their longevity and coherence under periodic driving.

Contribution

It provides a detailed analysis of Floquet sideband stability in strongly correlated systems using exact diagonalization and matrix product states, highlighting the effects of frequency, interactions, and noise.

Findings

Long-lived Floquet sidebands at high frequencies

Interaction-induced heating causes loss of coherence at low frequencies

Noise also suppresses Floquet sidebands

Abstract

For strongly correlated quantum systems, fundamental questions about the formation and stability of Floquet-Bloch sidebands (FBs) upon periodic driving remain unresolved. Here, we investigate the impact of electron-electron interactions and perturbations in the coherence of the driving on the lifetime of FBs by directly computing time-dependent single-particle spectral functions using exact diagonalization (ED) and matrix product states (MPS). We study interacting metallic and correlated insulating phases in a chain of correlated spinless fermions. At high-frequency driving we obtain clearly separated, long-lived FBs of the full many-body excitation continuum. However, if there is significant overlap of the features, which is more probable in the low-frequency regime, the interactions lead to strong heating, which results in a significant loss of quantum coherence and of the FBs. Similar suppression of FBs is obtained in the presence of noise. The emerging picture is further elucidated by the behavior of real-space single-particle propagators, of the energy gain, and of the momentum distribution function, which is related to a quantum Fisher information that is directly accessible by spectroscopic measurements.