Extensively degenerate superradiant phase in a giant-atom quantum Rabi ring

We show that an $N$-site quantum Rabi ring with matched giant-atom couplings has $2^N$ degenerate superradiant configurations as the atomic-to-cavity frequency ratio $η=Δ/ω$ tends to infinity. Each atom couples to two cavities two sites apart, and the photon hopping carries a phase $π/2$. Tuning the