  We report on a ballistic and fully tunable Josephson junction system
consisting of two parallel ribbons of graphene in contact with superconducting
MoRe. By electrostatic gating of the two individual graphene ribbons we gain
control over the real space distribution of the superconducting current
density, which can be continuously tuned between both ribbons. We extract the
respective gate dependent spatial distributions of the real space current
density by employing Fourier- and Hilbert transformations of the magnetic field
induced modulation of the critical current. This approach is fast and does not
rely on a symmetric current profile. It is therefore a universally applicable
tool, potentially useful for carefully adjusting Josephson junctions.

Mesoscale and Nanoscale Physics