Quantum metrology via chaos in a driven Bose-Josephson system

TL;DR

This paper demonstrates how chaotic dynamics in a driven Bose-Josephson system can generate entanglement and enable high-precision quantum measurements surpassing the standard quantum limit, with practical measurement strategies.

Contribution

It introduces a novel approach using chaos in a Bose-Josephson system for quantum metrology, achieving sub-SQL precision without initial entanglement.

Findings

Chaotic dynamics generate entanglement from non-entangled states.

Measurement precision surpasses the standard quantum limit.

Population measurements can realize sub-SQL precision.

Abstract

Entanglement preparation and signal accumulation are essential for quantum parameter estimation, which pose significant challenges to both theories and experiments. Here, we propose how to utilize chaotic dynamics in a periodically driven Bose-Josephson system for achieving a high-precision measurement beyond the standard quantum limit (SQL). Starting from an initial non-entangled state, the chaotic dynamics generates quantum entanglement and simultaneously encodes the parameter to be estimated. By using suitable chaotic dynamics, the ultimate measurement precision of the estimated parameter can beat the SQL. The sub-SQL measurement precision scaling can also be obtained via specific observables, such as population measurements, which can be realized with state-of-art techniques. Our study not only provides new insights for understanding quantum chaos and quantum-classical correspondence, but also is of promising applications in entanglement-enhanced quantum metrology.