  Topological protection of quantum correlations opens new horizons and
opportunities in quantum technologies. A variety of topological effects has
recently been observed in qubit networks. However, the experimental
identification of the topological phase still remains challenging, especially
in the entangled many-body case. Here, we propose an approach to independently
probe single- and two-photon topological invariants from the time evolution of
the two-photon state in a one-dimensional array of qubits. Extending the
bulk-boundary correspondence to the two-photon scenario, we show that an
appropriate choice of the initial state enables the retrieval of the
topological invariant for the different types of the two-photon states in the
interacting Su-Schrieffer-Heeger model. Our analysis of the Zak phase reveals
additional facets of topological protection in the case of collapse of bound
photon pairs.
