Decoherence-free radio-frequency-dressed subspaces

We study the spectral signatures and coherence properties of radiofrequency dressed hyperfine Zeeman sub-levels 87Rb. Experimentally, we engineer combinations static RF magnetic fields to modify response atomic spin states environmental field noise. demonstrate analytically experimentally existence 'magic' dressing conditions where decoherence due electromagnetic noise is strongly suppressed. Building upon this result, propose a bi-chromatic configuration that reduces global sensitivity ground low-frequency noise, enables simultaneous protection multiple transitions between two manifolds alkali species. Our methods produce protected any pair at arbitrary (low) DC-magnetic fields.