Enhanced resolution of lossy interferometry by coherent amplification

The aim of quantum sensing is to develop quantum methods to extract the maximum amount of information from a system with minimal disturbance upon it. Indeed, the possibility of performing precision measurements by adopting quantum resources can increase the achievable precision going beyond the semiclassical regime of operation. However the quantum states suitable for quantum metrology protocols, result extremely fragile under losses and decoherence, unavoidable in experimental implementations, destroying completely quantum benefits. This scenario puts the beating of realistic, noisy environments as the main challenge in developing quantum sensing.