  Realizing useful quantum operations with high fidelity is a two-task quantum
control problem wherein decoherence is to be suppressed and desired unitary
evolution is to be executed. The dynamical decoupling (DD) approach to
decoherence suppression has been fruitful but synthesizing DD fields with
certain quantum control fields may be experimentally demanding. In the context
of spin squeezing, here we explore an unforeseen possibility that continuous DD
fields may serve dual purposes at once. In particular, it is shown that a
rather simple configuration of DD fields can suppress collective decoherence
and yield a 1/N scaling of the squeezing performance (N is the number of
spins), thus making spin squeezing more robust to noise and much closer to the
so-called Heisenberg limit. The theoretical predictions should be within the
reach of current spin squeezing experiments.
