Protecting and enhancing spin squeezing under decoherence using weak   measurement
  We propose an efficient method to protect spin squeezing under the action of amplitude-damping, depolarizing and phase-damping channels based on measurement reversal from weak measurement, and consider an ensemble of N independent spin-1/2 particles with exchange symmetry. We find that spin squeezing can be enhanced greatly under three different decoherence channels and spin-squeezing sudden death (SSSD) can be avoided undergoing amplitude damping and phase-damping channels. 
Xiang-Ping Liao, Man-Sheng Rong, Mao-Fa Fang
quant-ph