  It is shown that recent experimental data on electronic transport through Pt
nanocontacts in the presence of hydrogen admit an explanation in terms of
topological and electron-electron correlation grounds. A model Hamiltonian,
which incorporates two orbitals on Pt atoms, a single orbital on hydrogens, and
the on-site Coulomb repulsion on the H atoms, is solved exactly, and connected
to Pt leads described by a Bethe lattice. When two weakly coupled H atoms are
placed between the Pt electrodes transversally to the transport direction (as
recently suggested) a Kondo effect related to the symmetry of the Pt-H
couplings, stabilizes the conductance around one quantum with a single channel
contributing to the current, in agreement with the experiments.
