Quantum Metrology: practically as perfect as it gets.

All modern technologies make abundant use of sensors. Their use ranges in everyday tools such as mobile technologies and GPS navigators, to industrial applications. The sought objective, common to all sensors, is to achieve the most accurate measurement of a given signal. The field that studies the best accuracy achievable is Quantum Metrology, which, by means of a robust control over the quantum properties of the device, allows to achieve the ultimate precision given by the Heisenberg limit.
“Just a spoonful of sugar” - together with a highly complex setup generating entangled photon-pairs - is what is needed to observe the precision improvements promised by quantum metrology: we will discuss an experiment in which the chirality of an aqueous solution of sucrose is tracked in time using quantum resources as it undergoes acid hydrolysis.
Another feature of metrology is that of providing measurement strategies to access quantities which cannot be directly observed. The field of ultrafast metrology has been extensively developed in the classical domain and only recently there have been attempts of extending it to its quantum counterpart. This will be the focus of the second part of the talk; in particular, we will explore if and how classical metrology techniques can be adapted to the spectral phase estimation of entangled photon pairs generated with Spontaneous Parametric Down Conversion (SPDC).