Anderson-Higgs polaritons [ 14 ,  15 ]. The matter constituent of these polaritons originates from the Anderson-Higgs amplitude mode in superconductors[16] (Fig.1). Anderson-Higgs polaritons are yet to be experimentally observed.

14. Zachary M. Raines, Andrew A. Allocca, Mohammad Hafezi, and Victor M. Galitski, “Cavity Higgs polaritons,” Physical Review Research 2, 013143 (2020).

15. Z. Sun, M.M. Fogler, D.N. Basov, and A. J. Millis, “Collective modes and THz near field response of superconductors,” Physical Review Research 2, 023413 (2020).