Quantum Metrology: Dynamics vs. Entanglement

TL;DR

This paper introduces a quantum metrology protocol that achieves super-Heisenberg scaling of measurement precision without entanglement, potentially applicable to Bose-Einstein condensates.

Contribution

It presents a novel protocol for quantum parameter estimation that surpasses traditional limits without requiring entanglement among constituents.

Findings

Achieves $1/n^{3/2}$ scaling in measurement uncertainty

Protocol does not generate entanglement among constituents

Potential implementation in two-component Bose-Einstein condensates

Abstract

A parameter whose coupling to a quantum probe of $n$ constituents includes all two-body interactions between the constituents can be measured with an uncertainty that scales as $1/n^{3/2}$, even when the constituents are initially unentangled. We devise a protocol that achieves the $1/n^{3/2}$ scaling without generating any entanglement among the constituents, and we suggest that the protocol might be implemented in a two-component Bose-Einstein condensate.