Superconducting-like response in driven systems near the Mott transition

We point out that fractionalized bosonic charge excitations can explain the recently discovered photo-induced superconducting-like response in $kappatext{-(ET})_2text{Cu}[text{N(CN)}_2]text{Br}$, 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.