RANDOMNESS EXTRACTION AND CLOCK SYNCHRONIZATION WITH CONTINUOUS PARAMETRIC DOWN-CONVERSION

Abstract

This thesis introduces two protocols related to secure communication: private randomness generation and clock synchronization. The first enables measuring a Bell violation with a continuous source of entangled photon pairs, which eliminates the intrinsic deadtime present in previous experiments conducted with pulsed sources. This dramatically reduces the total acquisition time required for generating private random numbers from a detection loophole-free Bell experiment, while maintaining a competitive rate. As the randomness generation rate depends on the rate of photon pairs detected, we also developed an algorithm that extracts photodetection times from overlapping pulses from our detectors, increasing the maximum detectable flux rate by an order of magnitude. In the second protocol, we demonstrate absolute clock synchronization between two spatially separated rubidium clocks with correlated photon pairs. A Bell inequality check allows signal verification. Protocol vulnerability is investigated by exploiting its reliance on a symmetric synchronization channel.