  We propose a scheme to implement geometric entangling gates for two logical
qubits in a coupled cavity system in decoherence-free subspaces. Each logical
qubit is encoded with two atoms trapped in a single cavity and the geometric
entangling gates are achieved by cavity coupling and controlling the external
classical laser fields. Based on the coupled cavity system, the scheme allows
the scalability for quantum computing and relaxes the requirement for
individually addressing atoms.
