Magnetic Dipolar Interaction between Hyperfine Clock States in a Planar Alkali Bose Gas

Abstract

In atomic systems, clock states feature a zero projection of the total angular momentum and thus a low sensitivity to magnetic fields. This makes them widely used for metrological applications like atomic fountains or gravimeters. Here, we show that a mixture of two such nonmagnetic states still displays magnetic dipole-dipole interactions comparable to the one expected for the other Zeeman states of the same atomic species. Using high-resolution spectroscopy of a planar gas of $^{87}\mathrm{Rb}$ atoms with a controlled in plane shape, we explore the effective isotropic and extensive character of these interactions and demonstrate their tunability. Our measurements set strong constraints on the relative values of the $s$-wave scattering lengths ${a}_{ij}$ involving the two clock states.