2025/09/10 by Figueiredo, J. L., Mendonça, J. T., Terças, H.
#FOS: Physical sciences #Optics (physics.optics) #Quantum Gases (cond-mat.quant-gas)
paper · doi:10.48550/arxiv.2509.09007
Supersolidity - simultaneous superfluid flow and crystalline order - has been realized in quantum atomic systems but remains unexplored in purely photonic platforms operating at weak light-matter coupling. We predict a supersolid phase of light in a plasma-filled optical microcavity, where photons acquire effective mass and interact via nonlocal, plasma-mediated nonlinearities. By deriving a Gross-Pitaevskii equation with a tunable photon-photon interaction kernel, we show that under coherent driving the cavity light field can spontaneously crystallize into a supersolid lattice via modulational instability. Crucially, this supersolid arises from a weak photon-electron coupling enabled by virtual electronic transitions, and it does not require hybrid polariton formation. Using doped semiconductor microcavities, we identify feasible conditions (electron densities ∼ 1010- 1011~cm-2 and optical intensities ∼ 102-104~W/cm2) for experimental realization. This work establishes plasmonic cavities as a platform for correlated photonic matter with emergent quantum order.