Quantum sensing of the phase space displacement parameters using a single trapped ion

TL;DR

This paper presents a quantum sensing protocol using a single trapped ion to accurately estimate phase space displacement parameters, achieving optimal measurement precision through quantum Fisher information analysis.

Contribution

The authors develop a novel quantum sensing method employing a single trapped ion to simultaneously estimate multiple displacement parameters with quantum-limited precision.

Findings

Efficient estimation of displacement parameters via atomic state measurements.

Introduction of a three-parameter protocol for comprehensive displacement detection.

Measurement strategy saturates the quantum Cramer-Rao bound.

Abstract

We introduce a quantum sensing protocol for detecting the parameters characterizing the phase space displacement by using a single trapped ion as a quantum probe. We show that thanks to the laser-induced coupling between the ion's internal states and the motion mode the estimation of the two conjugated parameters describing the displacement can be efficiently performed by a set of measurements of the atomic state populations. Furthermore, we introduce a three-parameter protocol capable to detect the magnitude, the transverse direction and the phase of the displacement. We characterize the uncertainty of the two- and three-parameter problems in terms of the Fisher information and show that state projective measurement saturates the fundamental quantum Cramer-Rao bound.