Interactions of ultracold atoms with magnetic fields from domain walls in nanowires

The interaction of ultra-cold atoms with magnetic microstructures has become the focus of many recent experiments [1]. We present progress towards the interaction of cold Rb atoms with the magnetic fields from domain walls in nanowires. Fig. 1 a) shows the out of plane field from such a domain wall. Micromagnetic simulations show that nanowires could be used to create atom traps with frequencies in the MHz regime [2]. Transparent substrates can be used so that the microscopic traps can be loaded from an optical lattice and the small amount of metal present means that the usual Johnson noise heating effects can be avoided and lifetimes of many seconds achieved. Since domain walls are mobile, transportable traps can be envisaged which can allow atoms to be brought into close proximity to allow interactions for quantum information processes.