  We theoretically study how to control transport, bound states, and resonant
states of a single photon in a one-dimensional coupled-cavity array. We find
that the transport of a single photon in the cavity array can be controlled by
tuning the frequency of either one or two cavities. If one of the cavities in
the array has a tunable frequency, and its frequency is tuned to be larger (or
smaller) than those of other cavities, then there is a photon bound state above
(or below) the energy band of the coupled cavity array. However, if two
cavities in the array have tunable frequencies, then there exist both bound
states and resonant states. When the frequencies of the two cavities are chosen
to be much larger than those of other cavities and the hopping couplings
between any two nearest-neighbor cavities are weak, a single photon with a
resonant wave vector can be trapped in the region between the two
frequency-tunable cavities. In this case, a quantum supercavity can be formed
by these two frequency-tunable cavities. We also study how to apply this photon
transport control to an array of coupled superconducting transmission line
resonators.
