More randomness from a prepare-and-measure scenario with independent devices

TL;DR

This paper introduces a new method to generate more genuine quantum randomness from untrusted devices in a prepare-and-measure setup by utilizing all observed probabilities to calculate min-entropy, outperforming previous protocols.

Contribution

The paper presents a novel approach that directly uses all observed probabilities to compute min-entropy, increasing the amount of genuine quantum randomness generated.

Findings

Higher min-entropy compared to previous methods.

More genuine quantum random numbers can be obtained.

Applicable to typical BB84 setups.

Abstract

How to generate genuine quantum randomness from untrusted devices is an important problem in quantum information processing. Inspired by previous work on a self-testing quantum random number generator [T. Lunghi et al., Phys. Rev. Lett. 114, 150501 (2015)], we present a method to generate quantum randomness from a prepare-and-measure scenario with independent devices. In existing protocols, the quantum randomness depends only on a witness value (e.g., Clauser-Horne-Shimony-Holt value), which is calculated with the observed probabilities. Differently, here all the observed probabilities are directly used to calculate the min-entropy in our method. Through numerical simulation, we find that the min-entropy of our proposed scheme is higher than that in the previous work when a typical untrusted Bennett-Brassard 1984 (BB84) setup is used. Consequently, thanks to the proposed method, more genuine quantum random numbers may be obtained than before.