Incompressible polaritons in a flat band

Matteo Biondi, Evert P. L. van Nieuwenburg, Gianni Blatter, Sebastian D. Huber, and Sebastian Schmidt

Institute for Theoretical Physics, ETH Zurich, Switzerland

We study the interplay of geometric frustration and interactions in a non-equilibrium photonic lattice system exhibiting a polariton flat band as described by a variant of the Jaynes-Cummings-Hubbard model. We develop a semi-analytic projective method and employ an open system version of the time-evolving block decimation algorithm (TEBD) in order to calculate the non-equilibrium steady state of the array subject to drive and dissipation. We find that frustration strongly enhances photon repulsion in a flat band leading to an incompressible state of light. The latter manifests itself in strong spatial correlations, i.e., on-site and nearest-neighbor anti-bunching combined with extended density-wave oscillations at larger distances. We propose a state-of-the-art circuit QED realization of our system, which is tunable in-situ.

Reference: arXiv:1502.07854