Floquet-engineered pair and single particle filter in the Fermi Hubbard model

TL;DR

This paper explores how Floquet driving can be used to create selective filters for pairs and single particles in the Fermi-Hubbard model, revealing distinct transmission behaviors that enable control over particle transport.

Contribution

It introduces a Floquet-based method to engineer filters that selectively transmit either pairs or single particles in the Fermi-Hubbard model, demonstrating control over particle transport.

Findings

Pairs show maximum transmission near the ratio of interaction to driving frequency.

Single particles exhibit maximum transmission at low driving amplitudes in the high frequency limit.

Filters can be designed to block single particles while allowing pairs to pass.

Abstract

We investigate the Fermi-Hubbard model with a Floquet-driven impurity in the form of a local time-oscillating potential. For strong attractive interactions a stable formation of pairs is observed. These pairs show a completely different transmission behavior than the transmission that is observed for the single unpaired particles. Whereas in the high frequency limit the single particles show a maximum of the transition at low driving amplitudes, the pairs display a pronounced maximum transmission when the amplitude of the driving lies close to the ratio of the interaction U and the driving frequency {\omega}. We use the distinct transmission behaviour to design filters for pairs or single particles, respectively. For example one can totally block the transmission of single particles through the driven impurity and allow only for the transmission of pairs. We quantify the quality of the designed filters.