Sub-quantum-limit interferometry

Yang Gao, Hwang Lee

We show that the parity measurement can be used as a universal detection scheme for the sub-shot-noise limit interferometry. The efforts to produce the desired input states can then be much reduced accordingly.

F. De Martini, G. Denardo, Anton Zeilinger

Rafał Demkowicz-Dobrzański, Marcin Jarzyna, Jan Kołodyński

Aravind Chiruvelli, Hwang Lee

We investigate the utility of parity detection to achieve Heisenberg-limited phase estimation for optical interferometry. We consider the parity detection with several input states that have been shown to exhibit sub-shot-noise interferometry with their respective detection schemes. We show that with parity detection, all these states achieve the sub-shot-noise limited phase uncertainty. Thus making the parity detection a unified detection strategy for quantum optical metrology. We also consider quantum states that are a combination of a NOON state and a dual-Fock state, which gives a great deal of freedom in the preparation of the input state, and is found to surpass the shot-noise limit.

Quentin Marolleau, Charlie Leprince, Victor Gondret +2 more

We study the feasibility of sub-shot-noise interferometry with imperfect detectors, starting from twin Fock states and two-mode squeezed vacuum states. We derive analytical expressions for the corresponding phase uncertainty. We find that one can achieve phase shift measurements below the standard quantum limit, as long as the losses are smaller than a given threshold, and that the measured phase is close enough to an optimal value. We provide our analytical formulas in a python package, accessible online.

Masahiro Kitagawa, Masahito Ueda