Quantum metric driven transition between superfluid and incoherent fluid
Phys. Rev. B 112, 014518 – Published 23 July, 2025
DOI: https://doi.org/10.1103/3pvf-1ckd
Abstract
We study the interplay between repulsive interaction and superfluidity in flat band systems. We consider spatially indirect excitons in the Lieb lattice bilayer as an example. We show that due to the presence of repulsive interaction, the excitons may form an incoherent fluid. With an increase of the quantum metric, the exciton fluid experiences a transition into the superfluid phase. This transition may be captured by a model of the Josephson junction array, which is beyond the mean field description.
