# Experimental Realization of Device-Independent Quantum Randomness Expansion

## TL;DR

This paper reports the first experimental demonstration of device-independent quantum randomness expansion, generating over 500 million quantum-proof random bits with high security and minimal soundness error, advancing practical quantum cryptography.

## Contribution

It presents the first experimental realization of device-independent quantum randomness expansion secure against quantum side information, using quantum probability estimation.

## Key findings

- Generated 5.47×10^8 quantum-proof random bits
- Expanded randomness by 1.08×10^8 bits in 13.1 hours
- Achieved a total soundness error of 4.6×10^{-10}

## Abstract

Randomness expansion where one generates a longer sequence of random numbers from a short one is viable in quantum mechanics but not allowed classically. Device-independent quantum randomness expansion provides a randomness resource of the highest security level. Here, we report the first experimental realization of device-independent quantum randomness expansion secure against quantum side information established through quantum probability estimation. We generate $5.47\times10^8$ quantum-proof random bits while consuming $4.39\times10^8$ bits of entropy, expanding our store of randomness by $1.08\times10^8$ bits at a latency of about $13.1$ h, with a total soundness error $4.6\times10^{-10}$. Device-independent quantum randomness expansion not only enriches our understanding of randomness but also sets a solid base to bring quantum-certifiable random bits into realistic applications.