  Electrons in a metal are indistinguishable particles that strongly interact
with other electrons and their environment. Isolating and detecting a single
flying electron after propagation to perform quantum optics like experiments at
the single electron level is therefore a challenging task. Up to date, only few
experiments have been performed in a high mobility two-dimensional electron gas
where the electron propagates almost ballistically. Flying electrons were
detected via the current generated by an ensemble of electrons and electron
correlations were encrypted in the current noise. Here we demonstrate the
experimental realisation of high efficiency single electron source and single
electron detector for a quantum medium where a single electron is propagating
isolated from the other electrons through a one-dimensional channel. The moving
potential is excited by a surface acoustic wave, which carries the single
electron along the 1D-channel at a speed of 3\mum/ns. When such a quantum
channel is placed between two quantum dots, a single electron can be
transported from one quantum dot to the other, which is several micrometres
apart, with a quantum efficiency of emission and detection of 96% and 92%,
respectively. Furthermore, the transfer of the electron can be triggered on a
timescale shorter than the coherence time T2* of GaAs spin qubits6. Our work
opens new avenues to study the teleportation of a single electron spin and the
distant interaction between spatially separated qubits in a condensed matter
system.
