# Detection of quantum signals free of classical noise via quantum correlation

## TL;DR

This paper introduces a novel quantum correlation-based protocol that isolates quantum signals from classical noise, surpassing traditional filtering techniques and leveraging the intrinsic quantum nature of systems for advanced quantum sensing.

## Contribution

The paper presents a new method utilizing quantum correlations to detect signals hidden in classical noise, expanding quantum sensing capabilities beyond conventional filtering.

## Key findings

- Successfully extracted a remote nuclear spin signal from classical noise
- Demonstrated quantum correlation as a new sensing degree of freedom
- Proposed a generalizable approach for quantum signal detection

## Abstract

Extracting useful signals is key to both classical and quantum technologies. Conventional noise filtering methods rely on different patterns of signal and noise in frequency or time domains, thus limiting their scope of application, especially in quantum sensing. Here, we propose a signal-nature-based (not signal-pattern-based) approach which singles out a quantum signal from its classical noise background by employing the intrinsic quantum nature of the system. We design a novel protocol to extract the Quantum Correlation signal and use it to single out the signal of a remote nuclear spin from its overwhelming classical noise backgrounds, which is impossible to be accomplished by conventional filter methods. Our work demonstrates the quantum/classical nature as a new degree of freedom in quantum sensing. The further generalization of this quantum nature-based method opens a new direction in quantum research.