Maximizing device-independent randomness from a Bell experiment by optimizing the measurement settings

TL;DR

This paper demonstrates how optimizing measurement settings in Bell experiments can enhance device-independent quantum randomness generation rates, revealing non-monotonic relationships with entanglement.

Contribution

It introduces a numerical optimization approach for measurement settings to maximize randomness rates in Bell experiments involving mixed two-qubit states.

Findings

Optimized measurements improve randomness generation rates.

Randomness rates are non-monotonic with entanglement.

Tomographic measurements yield specific randomness rates.

Abstract

The rates at which a user can generate device-independent quantum random numbers from a Bell-type experiment depend on the measurements that he performs. By numerically optimising over these measurements, we present lower bounds on the randomness generation rates for a family of two-qubit states composed from a mixture of partially entangled states and the completely mixed state. We also report on the randomness generation rates from a tomographic measurement. Interestingly in this case, the randomness generation rates are not monotonic functions of entanglement.