Driving transitions between spin states creates new ‘continuous dynamical decoupled’ states, sensitive to oscillating fields yet protected from lowfrequency drifts and inhomogeneities. We continuously observe an ultracold spin1 gas undergoing such decoupling, measuring the populations, splittings, and couplings of the new states in real time [1]. This characterization is completed during a single experimental preparation, rather than the hundreds required with projective measurement. We show that one statepair is protected to fourthorder with respect to field instabilities, higher than the quadratic suppression of standard decoupling. Combining continuous measurement with continuous decoupling will enable feedback and tracking capabilities for noiserobust atomic magnetometry. This work complements parallel measurements of the same rfdressed system by Trypogeorgos et al. using projective readout of dressed state populations at higher magnetic fields [2].
Update (28/12/2017): This paper has been accepted by Physical Review A.
[1] R. P. Anderson, M. J. Kewming, L. D. Turner. Continuously observing a dynamically decoupled spin1 quantum gas. arXiv:1706.08322.
[2] D. Trypogeorgos, A. ValdésCuriel, N. Lundblad, I. B. Spielman. Synthetic clock transitions via continuous dynamical decoupling. arXiv:1706.07876.


Continuous observation of continuous dynamical decoupling.