精密测量中的量子极限

Given a physical setup, what is the precision that can be obtained? In this paper, we firstly review the recently theoretical developments about the quantum parameter estimation. The measurement sensitivity can be improved from the Heisenberg limit (HL) to super-Heisenberg limit (SHL) by changing the coupling Hamiltonian from linear to nonlinear. Then we review some techniques which have been used to break through the standard quantum limit (SQL) and reach the HL in optical quantum metrology, and describe the experiment of nonlinear quantum metrology where the interaction among particles as a valuable resource can contribute to measurement sensitivity and give scaling beyond the HL. Finally, we introduce a potential new approach to the future developments of quantum metrology.