  Qubit initialization is critical for many quantum algorithms and error
correction schemes, and extensive efforts have been made to achieve this with
high speed and efficiency. Here we experimentally demonstrate a fast and high
fidelity reset scheme for tunable superconducting qubits. A rapid decay channel
is constructed by modulating the flux through a transmon qubit and realizing a
swap between the qubit and its readout resonator. The residual excited
population can be suppressed to 0.08% $\pm$ 0.08% within 34 ns, and the scheme
requires no additional chip architecture, projective measurements, or feedback
loops. In addition, the scheme has negligible effects on neighboring qubits,
and is therefore suitable for large-scale multi-qubit systems. Our method also
offers a way of entangling the qubit state with an itinerant single photon,
particularly useful in quantum communication and quantum network applications.
