  The Single Cooper Pair Josephson Transistor is a device that exhibits at the
same time charge quantization and phase coherence. Coherent quantum phase slip
phenomenon is "dual" the Josephson phase coherence while the charge
quantization is dual to the flux quantization. We present the experimental
demonstration and the theoretical description of a new superconducting device -
Single Flux Transistor, which is dual to the Single Cooper Pair Transistor. Our
transport measurements show the periodic modulation of the critical voltage by
the external magnetic field. The obtained current-voltage characteristics show
the hysteretic behavior, which we attribute to the intrinsic self-heating of
charge carriers.
