Experimental device-independent certified randomness generation with an instrumental causal structure

The intrinsic random nature of quantum physics offers novel tools for the generation of random numbers, a central challenge for a plethora of fields. Bell non-local correlations obtained by measurements on entangled states allow for the generation of bit strings whose randomness is guaranteed in a device-independent manner, i.e. without assumptions on the measurement and state-generation devices. Here, we generate this strong form of certified randomness on a new platform: the instrumental scenario, which is central to the field of causal inference. First, we theoretically show that intrinsically random bits can be extracted exploiting device-independent quantum instrumental-inequality violations. Then, we experimentally implement the corresponding randomness-generation protocol, which is secure against any quantum adversary, using entangled photon states and active feed-forward of information.
Furthermore, we show that, for low levels of noise, our protocol offers an advantage over its counterpart, based on the best-known Clauser-Horn-Shimony-Holt inequality, in Bell scenario.  

Link: https://www.nature.com/articles/s42005-020-0375-6

Iris Agresti, Davide Poderini, Leonardo Guerini, Michele Mancusi, Gonzalo Carvacho, Leandro Aolita, Daniel Cavalcanti, Rafael Chaves and Fabio Sciarrino,  Communications Physics volume 3, Article number: 110 (2020).