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Quantum Information and Measurement (QIM)

Quantum Randomness Expansion with Uncharacterized Homodyne Detection Secure against Quantum Side-Information

Ignatius William Primaatmaja, Jianran Zhang, Jing Yan Haw, Raymond Ho, Gong Zhang, Chao Wang, Charles Ci Wen Lim

Published Jan 1, 2021• 0 citations
Publisher

Abstract

We propose a quantum randomness expansion protocol based on untrusted homodyne detection. We certify the randomness of the output against quantum side-information without assuming that the devices behave identically and independently in each round.
DOI
10.1364/qim.2021.f2b.7

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Quantum random number generators promise perfectly unpredictable random numbers. A popular approach to quantum random number generation is homodyne measurements of the vacuum state, the ground state of the electro-magnetic field. Here we experimentally implement such a quantum random number generator, and derive a security proof that considers quantum side-information instead of classical side-information only. Based on the assumptions of Gaussianity and stationarity of noise processes, our security analysis furthermore includes correlations between consecutive measurement outcomes due to finite detection bandwidth, as well as analog-to-digital converter imperfections. We characterize our experimental realization by bounding measured parameters of the stochastic model determining the min-entropy of the system's measurement outcomes, and we demonstrate a real-time generation rate of 2.9 Gbit/s. Our generator follows a trusted, device-dependent, approach. By treating side-information quantum mechanically an important restriction on adversaries is removed, which usually was reserved to semi-device-independent and device-independent schemes.