Southwest Quantum Information and Technology

Random number generation for loophole free Bell tests

Presenting Author: Morgan Mitchell, (ICFO)
Contributing Author(s): Carlos Abellán, Waldimar Amaya, Valerio Pruneri

The current generation of loophole-free Bell tests places stringent requirements on the methods for choosing "unpredictable" measurement settings, including very low excess predictability, generation in very short time windows, and statistical assurances very different from those typically used to characterize randomness sources, e.g. the NIST test suite. We show how these requirements have been met using a combination of ultra-fast phase-diffusion random number generators, purpose-built real-time randomness extraction, and novel statistical metrology. The approach produces bits traceable to spontaneous-emission events less than 28 ns in the past, with excess predictability (beyond the ideal 1/2) of less than 10e−4, both with strong metrological assurances. The approach has been employed in recent experiments closing the detection efficiency and communication loopholes, and addressing the freedom-of-choice loophole [Hensen et al. Nature 526, 682 (2015), Giustina et al. Phys. Rev. Lett. (Dec 2015), Shalm et al. Phys. Rev. Lett. (Dec 2015)]. We discuss the strategies for randomness generation in non-quantum theories and some significant deviations from "common wisdom" about randomness extraction that arise in the Bell test context.

Read this article online: http://arxiv.org/abs/1506.02712

(Session 1 : Thursday from 9:30 am - 10:00 am)