General framework for estimating the ultimate precision limit in noisy quantum-enhanced metrology

Understand

The estimation of parameters characterizing dynamical processes is central to science and technology.

• The estimation error changes with the number N of resources employed in the experiment (which could quantify, for instance, the number of probes or the probing energy).
• Typically, it scales as 1/N^(1/2).
• Quantum strategies may improve the precision, for noiseless processes, by an extra factor 1/N^(1/2).