By investigating the transport behavior of an ultracold atomic Fermi gas, researchers at CNR-INO in Sesto Fiorentino, in collaboration with LENS and the University of Florence, have revealed for the first time a peculiar enhancement of the resistive conduction of neutral superfluids through a tunnel junction at low temperatures. The new study is published on Physical Review Letters.

The observed anomalous conductance is fostered by the coupling between the fermionic condensate with sound wave excitations via a tunnelling barrier, and it is tightly linked to charge neutrality. This behavior is indeed absent in electronic junctions, where Coulomb interactions inhibit sound waves and the conductance is essentially dominated by the tunneling of non-condensed fermionic quasiparticles.