Jonathan Barrett

A remarkable aspect of quantum theory is that certain measurement outcomes are entirely unpredictable to all possible observers. Such quantum events can be harnessed to generate numbers whose randomness is asserted based upon the underlying physical processes. We formally introduce, design, and experimentally demonstrate an ultrafast optical quantum random number generator that uses a totally untrusted photonic source. While considering completely general quantum attacks and using dedicated FPGA hardware for post-processing, we certify and generate in real time random numbers at a rate of 8.05 Gb/s with a composable security parameter of 10^{−10}. Composable security is the most stringent and useful security paradigm because any given protocol remains secure even if arbitrarily combined with other instances of the same, or other, protocols, thereby allowing the generated randomness to be utilized for arbitrary applications in cryptography and beyond. This work achieves the fastest generation of composably secure quantum random numbers ever reported.

Understanding the relation between randomness and non-locality is a fundamental question in quantum physics. The non-local correlations observed when measuring entangled quantum particles certify the presence of randomness in the measurement outputs in a way that is independent on the underlying physical realization of these correlations.