Searching for evidence of algorithmic randomness and incomputability in the output of quantum random number generators

Highlights: • Quantum random number generators can produce incomputable random strings. • Test two quantum random number generators for algorithmic randomness and incomputability. • Significantly increased statistical power over previous searches. Ideal quantum random number generators (QRNGs) can produce algorithmically random and thus incomputable sequences, in contrast to pseudo-random number generators. However, the verification of the presence of algorithmic randomness and incomputability is a nontrivial task. We present the results of a search for algorithmic randomness and incomputability in the output from two different QRNGs, performed by applying tests based on the Solovay–Strassen test of primality and the Chaitin–Schwartz theorem. The first QRNG uses measurements of quantum vacuum fluctuations. The second QRNG is based on polarization measurements on entangled single photons; for this generator, we use looped (and thus highly compressible) strings that also allow us to assess the ability of the tests to detect repeated bit patterns. Compared to a previous search for algorithmic randomness, our study increases statistical power by almost 3 orders of magnitude.