Microwave Atom Chip Design

We present work towards the design of a microwave atom chip. Such a chip can produce spin-specific traps using microwave near-field potentials based on the AC Zeeman effect. These potentials are able to trap any spin state and offer suppressed roughness when compared to traditional micro-magnetic chip traps. An atom chip with the ability to spatially control atoms based on their internal spin has applications in trapped atom interferometry and 1D many-body physics. We propose a design based on microstrip transmission lines, which generate traps by overlapping the near-fields of two or three nearby microstrip traces. In such configurations we are able to show the existence of co-located circular traps outside the plane of the chip. Axial confinement of the atoms can be realized through the use of a microwave lattice. The AC Zeeman trap offers unique experimental variables for controlling atoms not found in conventional DC magnetic chip traps: detuning, phase, and the use of circularly polarized magnetic fields. For the three-microstrip geometry, adjusting the phase of the center trace relative to the two outer traces results in the splitting of the trap in two horizontally, providing a potential mechanism for spatially splitting a collection of atoms. Simulations show that due to the proximity of multiple traces to one another, coupling between traces leads to altered power and phase causing the behavior of the trap to differ from simple predictions based on independent traces.