The parity operator: Applications in quantum metrology

In this paper, the authors review use of parity as a detection observable in quantum metrology and introduce some original findings with regard to measurement resolution Ramsey spectroscopy nondemolition measures atomic parity. Parity was first introduced context an alternative state detection. It later adapted for optical interferometry where it has been shown be optimal saturating Cramér–Rao bound path symmetric states. The include brief on basics phase estimation connection between parity-based Fisher information applies interferometry. also discuss efforts made experimental methods measuring photon-number close paper discussion parity, leading enhanced multi-atom spectroscopy. show how may construction high-precision clocks.