Atom Chip AC Zeeman Potentials: Trapping and Interferometry

Charles Fancher, Andrew J. Pyle, Austin R. Ziltz +1 more

Andrew P. Rotunno, Shuangli Du, S. Aubin

Alexander D. Cronin

William Miyahira, S. Aubin

Trapping and manipulating ultracold atoms through the use of atom chips offers the ability to engineer complex electromagnetic field geometries in a compact form factor. One of the primary limitations hindering their use is trap potential roughness which arises as a result of defects in the atom chip wires when atoms are brought close to the chip. This roughness can play a limiting role in atom interferometry and strong 1D confinement experiments. We present an initial experimental demonstration of atom chip potential roughness suppression using radio-frequency (RF) AC Zeeman (ACZ) potentials on an atom chip. Using ∼20 MHz RF magnetic near-fields from the chip to target intra-manifold transitions in the 87Rb ground state, we trap atoms in a spindependent ACZ potential. We compare the axial trapping potential for atoms in comparable 2-wire DC and AC Zeeman traps and show evidence of roughness suppression in the AC trap.

William Miyahira, Andrew P. Rotunno, Shuangli Du +1 more

We present a toolbox of microstrip building blocks for microwave atom chips geared towards trapped atom interferometry. Transverse trapping potentials based on the AC Zeeman (ACZ) effect can be formed from the combined microwave magnetic near fields of a pair or a triplet of parallel microstrip transmission lines. Axial confinement can be provided by a microwave lattice (standing wave) along the microstrip traces. Microwave fields provide additional parameters for dynamically adjusting ACZ potentials: detuning of the applied frequency to select atomic transitions and local polarization controlled by the relative phase in multiple microwave currents. Multiple ACZ traps and potentials, operating at different frequencies, can be targeted to different spin states simultaneously, thus enabling spin-specific manipulation of atoms and spin-dependent trapped atom interferometry.

B. Wirtschafter, Soizic Hello, Christoph Ira Westbrook +1 more

Atom chip based interferometry holds signicant promise for embedded precise measurements of time, accelerations, rotations, and magnetic fields. It can enable compact sensors for various carriers like planes, boats, and drones, making it advantageous for navigation applications. When measuring acceleration with a cold atom interferometer, it is necessary to separate the two states during the interferometry sequence. Microwave dressed potentials generated from CPWs within a magnetic trap are one approach to achieve such on-chip manipulation. Two specic challenges arise in this process. First, the microwave field emitted by a waveguide introduces an AC Zeeman shifts, leading to a bias phase in the interferometer output. Precise determination of this bias is necessary for accurate parameter readout. Second, positioning the atom trap accurately between the two waveguides is crucial to obtain the necessary symmetry during separation; otherwise, the contrast of the interferometer is signicantly reduced. To address these challenges, we present a method for measuring AC Zeeman shifts using Ramsey interferometry.