Spin Grouping in Ring Cavity and Its Protection on Entangled States Transfer

Long-range interactions are essential for large-scale quantum computation and quantum interconnections. Cavities provide a promising avenue to achieve long-range interaction by enhancing the coupling of remote qubits through shared cavity modes. In this Letter, we investigate a spin array coupled to a ring cavity supporting two counterpropagating modes, focusing on the system's eigenstates and spin dynamics in the low-excitation regime. We show that, under specific spatial configurations, the spins naturally self-organize into two groups, within which exciton transport is confined. This spin-grouping mechanism preserves coherence between spins across the two groups, and is leveraged to deterministically transfer entangled states between remote spin pairs with additional dynamical addressing. We further propose feasible implementations using atomic qubits or solid-state platforms. Our scheme enables entangling remote spins within a cavity, highlighting potential applications in scalable quantum information processing.