We propose and demonstrate a technique for quantum random number generation based on the random population of the output spatial modes of a beam splitter when both inputs are simultaneously fed with indistinguishable weak coherent states. We simulate and experimentally validate the probability of generation of random bits as a function of the average photon number per input, and compare it to the traditional approach of a single weak coherent state transmitted through a beam-splitter, showing an improvement of up to 32\%. The ensuing interference phenomenon reduces the probability of coincident counts between the detectors associated with bits 0 and 1, thus increasing the probability of occurrence of a valid output. A long bit string is assessed by a standard randomness test suite with good confidence. Our proposal can be easily implemented and opens attractive performance gains without a significant trade-off.
@article{arxiv.1608.05155,
title = {Quantum random number generation enhanced by weak-coherent states interference},
author = {T. Ferreira da Silva and G. B. Xavier and G. C. Amaral and G. P. Temporão and J. P. von der Weid},
journal= {arXiv preprint arXiv:1608.05155},
year = {2016}
}