# Quantum-Enhanced Noise Radar

## TL;DR

This paper introduces a practical quantum noise radar using two-mode squeezed states that outperform classical noise sources, demonstrated through microwave experiments showing significant advantages even with noise and loss.

## Contribution

It presents a new quantum illumination protocol that avoids joint measurements, enhancing practicality and demonstrating superior performance in microwave experiments.

## Key findings

- Quantum source outperforms classical noise source by up to tenfold.
- The protocol does not require quantum memory for the idler.
- Experimental validation shows robustness against noise and loss.

## Abstract

We propose a novel protocol for quantum illumination: a quantum-enhanced noise radar. A two-mode squeezed state, which exhibits continuous-variable entanglement between so-called signal and idler beams, is used as input to the radar system. Compared to existing proposals for quantum illumination, our protocol does not require joint measurement of the signal and idler beams. This greatly enhances the practicality of the system by, for instance, eliminating the need for a quantum memory to store the idler. We perform a proof-of-principle experiment in the microwave regime, directly comparing the performance of a two-mode squeezed source to an ideal classical noise source that saturates the classical bound for correlation. We find that, even in the presence of significant added noise and loss, the quantum source outperforms the classical source by as much as an order of magnitude.