Perfect Randomness from Imperfect Devices

Martin Sandfuchs

PhD student at the Quantum Information Theory Group ETH

Abstract

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Unlike their classical counterpart, quantum processes can produce fundamentally unpredictable bits. Unfortunately, the outputs of realistic quantum devices are neither uncorrelated nor uniform. Hence, we need a way of extracting perfect randomness from imperfect devices. To achieve this goal, we consider two quantum processes happening in spacelike separated locations. We then show that spacelike separation is sufficient for extracting uniform and uncorrelated bits. This improves over prior work which required assumptions that are hard to justify in practice.