Generation of fresh and pure random numbers for loophole-free Bell tests

TL;DR

This paper presents a method to generate highly unpredictable random numbers from spontaneous-emission events within 36 ns, ensuring the randomness meets the strict standards needed for loophole-free Bell tests of local realism.

Contribution

It introduces a novel randomness extraction technique from spontaneous-emission events that provides strong guarantees for use in quantum physics experiments.

Findings

Randomness with predictability below 10^-5 achieved

Generation of random bits within 36 ns of emission events

Suitable for loophole-free Bell tests

Abstract

We demonstrate extraction of randomness from spontaneous-emission events less than 36 ns in the past, giving output bits with excess predictability below $10^{-5}$ and strong metrological randomness assurances. This randomness generation strategy satisfies the stringent requirements for unpredictable basis choices in current "loophole-free Bell tests" of local realism [Hensen et al., Nature (London) 526, 682 (2015); Giustina et al., Phys. Rev. Lett. 115, 250401 (2015); Shalm et al., Phys. Rev. Lett. 115, 250402 (2015)].