Periodic array of Bose-Einstein condensates in a magnetic lattice

We report the realization of a periodic array of Bose-Einstein condensates (BECs) of Rb-87 F = 1 atoms trapped in a one-dimensional magnetic lattice close to the surface of an atom chip. A clear signature for the onset of BEC in the magnetic lattice is provided by in situ site-resolved radio-frequency spectra, which exhibit a pronounced bimodal distribution consisting of a narrow component characteristic of a BEC together with a broad thermal cloud component. Similar bimodal distributions are found for various sites across the magnetic lattice. The realization of a periodic array of BECs in a magnetic lattice represents a major step towards the implementation of magnetic lattices for quantum simulation of many-body condensed matter phenomena in lattices of complex geometry and arbitrary period.