Improved frequency standard via weighted graph states

We study the spin squeezing property of weighted graph states, which can be used to improve sensitivity in interferometry. We study the time evolution of spin squeezing under local decoherence acting independently on each qubit. Based on the analysis, the spin squeezing of the weighted graph states is somehow robust in the presence of decoherence and the decoherence limit in the improvement of the interferometric sensitivity is still achievable. Furthermore, one can obtain the optimal improvement of sensitivity by tuning the weighted of each edges of the weighted graph state.