Generation of a spin-squeezed state with trapped ions using a dressing   field
  We propose a method for generating a spin-squeezed state that is a symmetric Dicke state, with trapped ions using only global access. The eigenstates of the ions under a strong dressing field become symmetric Dicke states and the M$\o$lmer--S$\o$rensen interaction selectively couples one of them to an initially populated auxiliary state. A $\mid D_{2n}^n>$ state, which is maximally spin squeezed, can be generated with high fidelity using only square pulses. Using an adiabatic technique, the ideal maximally spin-squeezed state is generated. 
Atsushi Noguchi, Kenji Toyoda, Shinji Urabe
quant-ph