Quantum Cloning for Absolute Radiometry
Bruno Sanguinetti, Enrico Pomarico, Pavel Sekatski, Hugo Zbinden, Nicolas Gisin · Physical Review Letters · 2010
In the quantum regime information can be copied with only a finite fidelity. This fidelity gradually increases to 1 as the system becomes classical. In this Letter we show how this fact can be used to directly measure the amount of radiated power. We demonstrate how these principles can be used to build a practical primary standard.