  We propose and analyze a multiphoton-state coherent transport protocol in a
coupled-resonator quantum network. A multiphoton swap gate between two
antipodes can be achieved with neither external modulation nor coupling
strength engineering. Moreover, we extend this result to a coupled-resonator
chain of arbitrary length with different coupling strengths. Effects of
decoherence via quantum nondemolition interaction are studied with sources
including vacuum quantum fluctuation and bath thermal excitations when the bath
is in the thermal equilibrium state. These observations are helpful to
understand the decoherence effects on quantum communication in quantum
coupled-resonator systems.
