Ballistic transport, realized when the system size is smaller than the mean free path of energy carriers, is traditionally regarded as the ultimate limit for energy transfer. Here, we predict a superballistic radiative heat transport regime that surpasses this limit in dilute chains of plasmonic nanoparticles confined within cavities. This anomalous regime exhibits superlinear scaling of the effective thermal conductivity (k ~L^1.5) and originates from the amplification of long-range interactions mediated by cavity-guided modes. Our results establish a framework for ultrafast photonic heat transport and open pathways for thermal management, information processing and energy transfer in quantum and nanoscale systems.
Categories: physics.optics cond-mat.mes-hall