High fidelity transfer of an arbitrary quantum state between harmonic oscillators

It is shown that by switching a specific time-dependent interaction between a harmonic oscillator and a transmission line (a waveguide, an optical fiber, etc.) the quantum state of the oscillator can be transferred into that of another oscillator coupled to the distant other end of the transmission line. The fidelity that can be achieved within a transfer time T approaches 1 exponentially in $gamma$ T where $gamma$ is a characteristic damping rate. Hence, a good fidelity is achieved even for a transfer time of the order of few damping times. Some implementations are discussed.