Magnetic trapping of spin-zero neutral atoms for spaceborne quantum sensors

Pioneering cold-atom experiments using NASA’s Cold Atom Lab in Earth orbit have observed magnetically confined halo-like clouds of spin-zero neutral atoms, which are in Zeeman states with magnetic quantum number m_f=0. These magnetically insensitive halo-clouds formed from the primary trap of a Bose-Einstein condensate and a thermal cloud of atoms in states with non-zero magnetic quantum numbers (m_f=2 and m_f=1). On Earth the gravitational force overpowers the magnetic trapping forces on these spin-zero atoms, but in microgravity the quadratic Zeeman effect enables an effective trapping potential and observable clouds held in very low frequency traps. Inspired by these observations, we theoretically explore techniques to produce, trap and control ultracold neutral atoms in magnetically insensitive Zeeman states with an atom chip-based system. In particular, we investigate the feasibility of developing a source of ultracold atoms trapped in spin-zero states in a quadratic-Zeeman-based trap using mean-field theory. This unique source would be insensitive to weak background fields, and we explore the robustness of quadratic Zeeman traps to magnetic fields and gradients, as well as the fragmentation of condensates held in atom chip traps. Additionally, we consider the feasibility of utilizing quadratic-Zeeman-based traps in the design of atom interferometers and inertial sensors.