Pairwise concurrence in cyclically symmetric quantum states

We provide an initial characterization of pairwise concurrence in quantum states which are invariant under cyclic permutations of party labeling. We prove that maximal entanglement can be entirely described by adjacent pairs, then give explicit descriptions of those states in specific subsets of four- and five-qubit states (X states). We also construct a monogamy bound on shared concurrences in the same subsets in four and five qubits, finding that above nonmaximal entanglement thresholds, no other entanglements are possible.