Superconducting-like response in driven systems near the Mott transition

TL;DR

This paper proposes that fractionalized bosonic charge excitations explain the photo-induced superconducting-like response observed in a near-Mott transition organic metal, suggesting a non-equilibrium condensate driven by laser excitation.

Contribution

It introduces a novel explanation for the superconducting-like response via fractionalization and non-equilibrium condensates in driven systems near the Mott transition.

Findings

Fractionalized bosonic charge excitations can produce a narrow Drude peak.

Photo-induced response is explained as a non-equilibrium condensate.

Proposal can be tested in spin liquids and cold atom systems.

Abstract

We point out that fractionalized bosonic charge excitations can explain the recently discovered photo-induced superconducting-like response in $\kappa\text{-(ET})_2\text{Cu}[\text{N(CN)}_2]\text{Br}$, an organic metal close to the Mott transition. The pump laser exerts a periodic drive on the fractionalized field, creating a non-equilibrium condensate, which gives a Drude peak much narrower than the equilibrium scattering rate, hence superconducting-like response. Our proposal illuminates new possibilities of detecting fractionalization and can be readily tested in spin liquid candidates and in cold atom systems.