Qiang Zhang, Dehuan Kong, Yebing Wang, Hongxin Zou, Hong Chang

 Abstract: We describe a dual-entropy-source quantum random number generator based on atomic spontaneous emission. Using the intensity fluctuations of a coherent beam to modulate the detuning frequency of the driving field, the atomic ensemble exhibits larger fluctuations of the spontaneous emission noise. The quantum-to-classical-noise ratio of the measured noise is increased to 10.14 dB. After post-processing, a string of random numbers at rates up to 5.12 Mb/s is extracted, which passes all the NIST tests. The presented scheme shows the feasibility to combine multiple independent randomness sources to produce secure quantum random bits.

 Key Words: Random number generator, Quantum optics, Atomic fluorescence