If implemented using switches based on the Josephson effect like here, then no. The thickness of the required insulating barrier presents a hard lower limit to

If implemented using switches based on the Josephson effect like here, then no. The thickness of the required insulating barrier presents a hard lower limit to the structure size. The actual value of that limit depends on the material used and the particular implementation of the Josephson junction, of which there seems to be quite a few. So the limit depends on how thin the barrier can be made.