On-chip semi-device-independent quantum random number generator exploiting contextuality

TL;DR

This paper demonstrates a semi-device-independent quantum random number generator using integrated silicon photonics and contextuality violation, achieving certified randomness without entanglement and suitable for practical quantum networks.

Contribution

It introduces a novel on-chip QRNG based on contextuality inequality violation, combining integrated photonics with a security certification method without entanglement.

Findings

Achieved a contextuality violation exceeding classical bounds by over 10σ.

Certified a min-entropy of 0.077 bits per round, enabling 21.7 bits/s randomness generation.

Demonstrated a practical, integrated approach for secure quantum randomness generation.

Abstract

We present a semi-device-independent quantum random number generator (QRNG) based on the violation of a contextuality inequality, implemented by the integration of two silicon photonic chips. Our system combines a heralded single-photon source with a reconfigurable interferometric mesh to implement qutrit state preparation, transformations, and measurements suitable for testing a KCBS contextuality inequality. This architecture enables the generation of random numbers from the intrinsic randomness of single-photon interference in a complex optical network, while simultaneously allowing a quantitative certification of their security without requiring entanglement. We observe a contextuality violation exceeding the classical bound by more than 10{\sigma}, unambiguously confirming non-classical behavior. From this violation, we certify a conditional min-entropy per experimental round of Hmin = 0.077 +- 0.002, derived via a tailored semidefinite-programming-based security analysis. Each measurement outcome therefore contains at least 0.077 +- 0.002 bits of extractable genuine randomness, corresponding to an asymptotic generation rate of 21.7 +- 0.5 bits/s. These results establish a viable route towards general-purpose, untrusted quantum random number generators compatible with practical integrated photonic quantum networks.