Precision protection through multi-body indirect correlations and the reconstruction of stable probe qubit system

The obstacle restricting us to generalize the ideal quantum metrology scheme to practice is the decay of the precision of estimation induced by the environment. When the parameter to be estimated is the phase parameter of atomic state, the loss of precision is caused by the spontaneous emission of the atom, which is the result of the interaction between the atom and the background quantum fields. Since the probe qubit constructed by the ground state and excited state of single atom is sensitive to the environment, we have provided schemes to use two proper states of n proper arrangement atoms as the new stable qubit states instead of the usual ground and excited state of single atom, to reduce the decay rate of the precision of estimation through the multi-atom indirect correlations.