Parity of polaritons in a molecular aggregate coupled to a single-mode cavity.

We investigated the parity of polaritons, particularly the parity of topological polariton states resulting from light fields, in a molecular aggregate with uniform and alternating excitation transfer interaction coupled to a single-mode cavity. We find that all polariton states are with even parity, in terms of parity conservation, and the even-parity edge states of the Su-Schrieffer-Heeger model with alternating excitation transfer interaction induce even-parity topological polariton states. Thus, the odd-parity edge states are almost unaffected. The original odd-parity edge state is then affected with respect to the parity non-conservation case, i.e. the occupation number of the edge states shifts from one edge to another. This result entails the preparation of edge states from the photonic excited states through an adiabatic process.