Metrology using atoms in an array of double-well potentials

TL;DR

This paper proposes a scalable method to generate entangled states in a 1D array of double-well potentials with Bose-Einstein condensates, enhancing quantum sensor sensitivity beyond classical limits.

Contribution

It introduces a novel approach using beam-splitting in a 1D array to produce entanglement for quantum metrology, demonstrating improved sensitivity.

Findings

Entanglement improves sensor sensitivity beyond standard quantum limit

Optimal measurement saturates quantum Cramer-Rao bound

Atomic fluctuations are accounted for in analysis

Abstract

Quantum effects, such as entanglement, Einstein-Podolsky-Rosen steering, and Bell correlations, can enhance metrological sensitivity beyond the standard quantum limit. These correlations are typically generated through interactions between atoms or molecules, or during the passage of a laser pulse through a birefringent crystal. Here, we consider an alternative method of generating scalable, many-body entangled states, and demonstrate their usability for quantum-enhanced metrology. Our setup is a one-dimensional (1D) array of double-well potentials holding independent and uncorrelated Bose-Einstein condensates. The beam-splitting transformation mixes the signal between adjacent wells and yields a strongly entangled state through a many-body equivalent of the Hong-Ou-Mandel effect. We demonstrate this entanglement can improve the sensitivity of quantum sensors. In our analysis, we account for the effects of atomic fluctuations and identify the optimal measurement that saturates the quantum Cramer-Rao bound.