Quantum Cramer-Rao bound and parity measurement
Aravind Chiruvelli, Hwang Lee · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2010
We show, by using parity detection, that the phase estimate obtained from the linear error propagation formula, indeed saturates the lower bound set by maximizing quantum Fisher information for several of the well-known states, proposed for the Heisenberg limited interferometry. Our results show that one can achieve the quantum Cram´er-Rao bound, by simply counting the number of photons which is not very far from actual realization.