Trapping ultracold atoms in a sub-micron-period triangular magnetic lattice
AbstractWe report the trapping of ultracold Rb87 atoms in a 0.7-μm-period two-dimensional triangular magnetic lattice on an atom chip. The magnetic lattice is created by a lithographically patterned magnetic Co/Pd multilayer film plus bias fields. Rubidium atoms in the |F=1,mF=−1〉 low-field seeking state are trapped at estimated distances down to about 100nm from the chip surface and with calculated mean trapping frequencies up to about 800kHz. The measured lifetimes of the atoms trapped in the magnetic lattice are in the range 0.4–1.7ms, depending on distance from the chip surface. Model calculations suggest the trap lifetimes are currently limited mainly by losses due to one-dimensional thermal evaporation following loading of the atoms from the Z-wire trap into the very tight magnetic lattice traps, rather than by fundamental loss processes such as surface interactions, three-body recombination, or spin flips due to Johnson magnetic noise. The trapping of atoms in a 0.7-μm-period magnetic lattice represents a significant step toward using magnetic lattices for quantum tunneling experiments and to simulate condensed matter and many-body phenomena in nontrivial lattice geometries.