Fig. 1: Microwave enhancement of superconductivity in flat band superconductors governed by quantum geometry.
From: Quantum geometry induced microwave enhancement of superconducting order in flat bands
a A microwave circuit with flat band superconductor for which we have picked twisted bilayer graphene (TBG). b When the superconductor is driven at subgap frequencies the quasiparticle spectrum is cooled-off at band bottom as thermally available quasiparticles are excited to higher energies via inelastic radiative scattering where momentum exhange is provided by disorder. In particular for flat bands, the nonequilibrium excitations are achieved via virtual transitions to proximity bands which are captured in quantum geometry. c The quantum geometric origin of nonequilibrium dyanmics in flat band superconductors is revealed by disorder corrected velocity vertex from where we can obtain the absorption determined by weighted interband quantum connection, see Eq. (7).
