Aspects of Quantum Random Number Generation

• Applicant: Dr. Rene Schwonnek
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 498116994

Random numbers are the central resource for almost all, quantum and classical, cryptographic primitives. As such, a reliable source of random numbers is vital: a good random number must unpredictable and private. Violations of these requirements are a serious security issue and may even cause a full breakdown of a whole cryptographic infrastructure. However, ensuring that these requirements are properly fulfilled imposes a hard challenge, both, in theory and in practice. Quantum random number generators (QRNGs) allow us to tackle this challenge. In contrast to classical physics, quantum physics provides us with the tools to give mathematically precise and practically testable guarantees on the unpredictability and privacy of a generated random number: ‘true randomness’ from a quantum experiment can be directly traced back to the fundamental and inevitable statistical nature of this theory. Privacy can be concluded from the fact that a pure quantum state has no correlation to any environment. The presence of those features can be quantitatively certified during the run-time of a protocol by the uncertainty principle. The scope of this project is to define, investigate, and also experimentally implement an advanced class of QRNG protocols. We want to take all steps on the path that leads to the demonstration of a new technology: (i) Building up a general theoretical framework and new mathematical methods (ii) Analyze existing and develop new protocols. (iii) Specify and implement a protocol for an explicit experimental platform and provide a full (finite block-length) security analysis. The result of this will be a source of random numbers that can be reliably used in further cryptographic protocols without compromising them. We will properly address and analyze certain side-channels, which open up security hazards in previous works, and demonstrate that the vital features provided by quantum physics can be fully and practically implemented, by only imposing a minimal set of assumptions.The project will be hosted by the group for theoretical quantum optics of Prof. Otfried Gühne in Siegen, the experimental demonstration will be implemented by the group of Prof. Ilja Gerhardt in Hannover, and the analysis of finite block length effects will be done in cooperation with the group of Prof. Renato Renner at the ETH in Zürich. My vision of this project is to showcase that the sometimes persistent seeming gaps between fundamental theoretical physics, practical experimental capabilities and modern developments in information theory can be successfully bridged to take a further step on our journey towards a quantum future.

• DFG Programme: WBP Position