Device-independent, megabit-rate quantum random number generator with beam-splitter-free architecture and live Bell test certification (2412.18285v2)

Abstract: Device-independent quantum random number generators (DI-QRNGs) are crucial for information processing, ensuring certified quantumness and genuine randomness. However, existing implementations often face low bit rates due to quantumness testing challenges. Here, we present a high-bit-rate DI-QRNG with live quantumness certification through the Bell test. Using spontaneous parametric down-conversion in a polarization Sagnac interferometer, we generate entangled pair-photons at diametrically opposite points on an annular ring with strong spatial and temporal correlations. Dividing the ring into six diametrically opposite sections, we create three entangled photon sources that exhibit bias-free quantum mechanical randomness from a single resource. By utilizing the coincidence counts of pair-photons from two sources, we generate raw bits, while the third source simultaneously measures the Bell's parameter without any loss of QRNG bits. We have generated 90 million raw bits in 46.4 seconds with the Bell parameter (S $>$ 2), with a minimum entropy extraction ratio exceeding 97$\%$. Post-processed using a Toeplitz matrix, the DI-QRNG achieves a bit rate of 1.8 Mbps, passing all NIST 800-22 and TestU01 tests. In the absence of Bell's parameter for a non-maximally entangled state, $g^{(2)}(0)$ can be the metric for quantumness measure. Scalable and beam-splitter-free, this megabit-rate DI-QRNG is ideal for practical applications.