Quantum Lunch: Semi-device-independent quantum randomness generation

Speaker:
Jonatan Bohr Brask from University of Geneva

Title:
Semi-device-independent quantum randomness generation

Abstract:
The generation of random numbers is an important task in modern science and technology, from cryptography and gambling to numerical simulation of physical and biological systems. Exploiting the inherent randomness in quantum processes enables the generation of high-quality randomness. This can be done under different levels of trust in the devices used, from completely device dependent, where a full quantum description of the devices is assumed, to completely device independent, were the inner workings of the devices can be unknown and randomness is certified by the violation of a Bell inequality. The former approach generally gives high rates, but a full characterisation of the devices may be difficult to obtain or verify, while the latter is very challenging to implement at present, leading to low rates.

 It is therefore interesting to explore the intermediate regime, to identify an optimal trade-off between ease of implementation and trust in the devices. In this talk, I will introduce the different settings for quantum randomness generation, and review two recent experiments from Geneva, combining high rates with a low level of trust. The protocols are based respectively on testing a dimension witness and on unambiguous state discrimination, and allow the user to monitor the entropy of the generated data in real time.