Bloch oscillations of a Bose-Einstein condensate in a subwavelength optical lattice

We report on experiments studying the transport properties of an atomic Bose-Einstein condensate in an optical lattice of spatial period $\ensuremath{\lambda}∕2n$, where $n$ is an integer, realized with the dispersion of multiphoton Raman transitions. We observe Bloch oscillations, as a clear effect of quantum transport, in a subwavelength-scale periodicity lattice. An unusually large tunneling coupling between lattice sites is evident from the measured effective mass. Future prospects of the different lattice structures are expected in the search for new quantum phases in tailored lattice structures up to quantum computing in optical nanopotentials.