  This paper uncovers the formation of topological edge polaritons that are
induced by the presence of quantum vacuum. Such quantum-vacuum-induced edge
polaritons could be achieved in a system of spinful fermionic lattice under
appropriate interaction with a single photonic mode. In the absence of the
light-matter coupling, the system is shown to be topologically trivial, which
consequently does not support edge modes. By employing Floquet theory, the
system is also found to be topologically trivial in the classical light limit,
i.e., at very small light-matter coupling but very large number of photons. On
the other hand, by treating both the fermionic and photonic degrees of freedom
quantum mechanically, the system becomes topologically nontrivial in the full
(fermionic+photonic) Hilbert space, which manifests itself as a pair of
topological (almost) zero energy eigenstates localized near each lattice's edge
and with very small mean photon number. Finally, the robustness of such
quantum-vacuum-induced edge polaritons against spatial disorder and
counterrotating coupling effect is explicitly demonstrated.
