Efficient verification of entangled continuous-variable quantum states with local measurements

TL;DR

This paper introduces a systematic, efficient method for verifying entangled continuous-variable quantum states using only local measurements, significantly outperforming traditional quantum tomography.

Contribution

The work presents a novel framework for verifying entangled continuous-variable states with local measurements, achieving quadratic efficiency improvements over existing methods.

Findings

Successfully verified entangled two-mode coherent states

Extended the verification protocol to multimode states

Achieved unconditionally high verification efficiency

Abstract

Continuous-variable quantum states are of particular importance in various quantum information processing tasks including quantum communication and quantum sensing. However, a bottleneck has emerged with the fast increasing in size of the quantum systems which severely hinders their efficient characterization. In this work, we establish a systematic framework for verifying entangled continuous-variable quantum states by employing local measurements only. Our protocol is able to achieve the unconditionally high verification efficiency which is quadratically better than quantum tomography as well as other nontomographic methods. Specifically, we demonstrate the power of our protocol by showing the efficient verification of entangled two-mode and multimode coherent states with local measurements.