  Decoherence of quantum objects in noisy environments is important in quantum
sciences and technologies. It is generally believed that different processes
coupled to the same noise source should have similar decoherence behaviors and
stronger noises would cause faster decoherence. Here we show that in a quantum
bath, the case can be the opposite. In particular, we predict that the
multi-transition of a nitrogen-vacancy center spin-1 in diamond can have longer
coherence time than the single-transitions, even though the former suffers
twice stronger noises from the nuclear spin bath than the latter. This
anomalous decoherence effect is due to manipulation of the bath evolution via
flips of the center spin.
