  We present an experimental demonstration as well as a theoretical model of an
integrated circuit designed for the manipulation of a microwave field down to
the single-photon level. The device is made of a superconducting resonator
coupled to a transmission line via a second frequency-tunable resonator. The
tunable resonator can be used as a tunable coupler between the fixed resonator
and the transmission line. Moreover, the manipulation of the microwave field
between the two resonators is possible. In particular, we demonstrate the
swapping of the field from one resonator to the other by pulsing the frequency
detuning between the two resonators. The behavior of the system, which
determines how the device can be operated, is analyzed as a function of one key
parameter of the system, the damping ratio of the coupled resonators. We show a
good agreement between experiments and simulations, realized by solving a set
of coupled differential equations.
