Enhancing Dynamic Range of Sub-Quantum-Limit Measurements via Quantum Deamplification

TL;DR

This paper introduces a quantum deamplification technique that extends the dynamic range of measurements with minimal sensitivity loss, using sequential spin-squeezing and entangled states to improve quantum metrology applications.

Contribution

The authors propose a novel quantum deamplification method that enhances dynamic range in quantum measurements while maintaining high sensitivity, utilizing two-axis counter-twisting dynamics and hybrid schemes.

Findings

Approaching the quantum interferometer limit with two-axis counter-twisting.

Sequential quantum deamplification extends dynamic range.

Hybrid sensing improves robustness against detection noise.

Abstract

Balancing high sensitivity with a broad dynamic range is a fundamental challenge in measurement science, as improving one often compromises the other. While traditional quantum metrology has prioritized enhancing local sensitivity, a large dynamic range is crucial for applications such as atomic clocks, where extended phase interrogation times contribute to wider phase range. In this Letter, we introduce a novel quantum deamplification mechanism that extends dynamic range at a minimal cost of sensitivity. Our approach uses two sequential spin-squeezing operations to generate and detect an entangled probe state, respectively. We demonstrate that the optimal quantum interferometer limit can be approached through two-axis counter-twisting dynamics. Further expansion of dynamic range is possible by using sequential quantum deamplification interspersed with phase encoding processes. Additionally, we show that robustness against detection noise can be enhanced by a hybrid sensing scheme that combines quantum deamplification with quantum amplification. Our protocol is within the reach of state-of-the-art atomic-molecular-optical platforms, offering a scalable, noise-resilient pathway for entanglement-enhanced metrology.