Microwave ring trap for ultracold atoms

We propose a ring trap based on spatially modulated coupling of the hyperfine manifolds of the atomic ground state, whose degeneracy is lifted by a bias field BDC. This results in a ring trap operating at microwave frequencies rather than radio-frequency. A sketched of our proposal is shown in a figure in this paper, where typical values of relevant parameters are included. We perform calculations for ⁸⁷Rb and study conditions under which this trap can be realized, including considerations about the life-time of trapped states.