RANDOMNESS EXTRACTION FROM DETECTION LOOPHOLE-FREE BELL VIOLATION WITH CONTINUOUS PARAMETRIC DOWN-CONVERSION

Abstract

Quantum entanglement provides sources of randomness that can be certified as being uncorrelated with any outside process or variable. Certified private randomness can be extracted by a system that violates the Bell inequality. The randomness extraction rate depends on the observed violation and on the repetition rate of the Bell test.

In this thesis, polarization-entangled photon pairs generated by spontaneous parametric down conversion, together with near-unit detection efficiency transition-edge sensors are used to demonstrate a detection loophole-free Bell violation.

We use a continuous wave source and organize detection events in uniform time bins to define a measurement round for the Bell test. A relatively high Bell violation is observed with our system. The measurement outcome also shows that the observed violation and randomness generation rates depend on the time bin length. Using an extractor secure against a quantum adversary, we calculate an asymptotic rate of ≈ 1300 random bits/s.