Certified Randomness From Steering Using Sequential Measurements
This work addresses the problem of practical randomness certification for quantum technologies, particularly in asymmetric setups like ion-photon networks, but it is incremental as it adapts previous methods to a less stringent scenario.
The paper tackles the challenge of generating certifiable randomness in quantum systems by proposing a one-sided device-independent scenario, where some devices are trusted, to reduce experimental complexity compared to fully device-independent methods. It provides theoretical bounds and a protocol for unbounded randomness certification, with numerical results demonstrating feasibility on near-term quantum platforms.
The generation of certifiable randomness is one of the most promising applications of quantum technologies. Furthermore, the intrinsic non-locality of quantum correlations allow us to certify randomness in a device-independent way, i.e. one need not make assumptions about the devices used. Due to the work of Curchod et. al., a single entangled two-qubit pure state can be used to produce arbitrary amounts of certified randomness. However, the obtaining of this randomness is experimentally challenging as it requires a large number of measurements, both projective and general. Motivated by these difficulties in the device-independent setting, we instead consider the scenario of one-sided device independence where certain devices are trusted, and others not; a scenario motivated by asymmetric experimental set-ups such as ion-photon networks. We show how certain aspects of previous work can be adapted to this scenario and provide theoretical bounds on the amount of randomness which can be certified. Furthermore, we give a protocol for unbounded randomness certification in this scenario, and provide numerical results demonstrating the protocol in the ideal case. Finally, we numerically test the possibility of implementing this scheme on near-term quantum technologies, by considering the performance of the protocol on several physical platforms.