Unlocking Heisenberg Sensitivity with Sequential Weak Measurement Preparation

TL;DR

This paper introduces a sequential measurement protocol to generate highly entangled spin states for quantum metrology, achieving Heisenberg-limited sensitivity without nonlinear interactions, suitable for current experiments.

Contribution

A novel sequential measurement-based protocol for preparing large-scale entangled states that enable quantum-enhanced metrology at the Heisenberg limit.

Findings

Generated highly entangled spin states without nonlinear interactions.

Achieved Heisenberg-limited sensitivity under symmetric coupling.

Identified optimal preparation windows for asymmetric couplings.

Abstract

We propose a state preparation protocol based on sequential measurements of a central spin coupled with a spin ensemble, and investigate the usefulness of the generated multi-spin states for quantum enhanced metrology. Our protocol is shown to generate highly entangled spin states, devoid of the necessity for non-linear spin interactions. The metrological sensitivity of the resulting state surpasses the standard quantum limit, reaching the Heisenberg limit under symmetric coupling strength conditions. We also explore asymmetric coupling strengths, identifying specific preparation windows in time for optimal sensitivity. Our findings introduce a novel method for generating large-scale, non-classical, entangled states, enabling quantum-enhanced metrology within current experimental capabilities.