  We present a new robust decoupling scheme suitable for levels with either
half integer or integer angular momentum states. Through continuous dynamical
decoupling techniques, we create a protected qubit subspace, utilizing a
multi-state qubit construction. Remarkably, the multi-state system can also be
comprised of multiple sub-states within a single level. Our scheme can be
realized with state-of-the-art experimental setups and thus has immediate
applications for quantum information science. While the scheme is general and
relevant for a multitude of solid state and atomic systems, we analyze its
performance for the case composed of trapped ions. Explicitly, we show how
single qubit gates and an ensemble coupling to a cavity mode can be implemented
efficiently. The scheme predicts a coherence time of ~1 second, as compared to
typically a few milliseconds for the bare states.
