Phase sensitivity at the Heisenberg limit in an SU(1,1) interferometer via parity detection

TL;DR

This paper theoretically demonstrates that an SU(1,1) interferometer with parity detection can achieve phase sensitivity at the Heisenberg limit, providing optimal conditions and deriving the quantum Cramér-Rao bound.

Contribution

It introduces a method to reach the Heisenberg limit in phase sensitivity using an SU(1,1) interferometer with parity detection, including optimal conditions and quantum bounds.

Findings

Sensitivity approaches the Heisenberg limit

Optimal conditions for phase estimation are identified

Quantum Cramér-Rao bound is derived

Abstract

We theoretically investigate the phase sensitivity with parity detection on an SU(1,1) interferometer with a coherent state combined with a squeezed vacuum state. This interferometer is formed with two parametric amplifiers for beam splitting and recombination instead of beam splitters. We show that the sensitivity of estimation phase approaches Heisenberg limit and give the corresponding optimal condition. Moreover, we derive the quantum Cram\'er-Rao bound of the SU(1,1) interferometer.