Research On Semi-device-independent Quantum Random Number Generator With Practical Sources

Nowadays,how to generate great random numbers with high speed is a basic and important scientific problem,since random numbers play a very important role in the fields of cryptography,algorithms and simulation.Although some computergenerated random numbers can pass various number verification procedures,they are determined by given algorithm and seed,which in principle can be predicted.They are so-called pseudo-random numbers.Recently,with the development of quantum information technology,we have discovered that we can use the inherent randomness of quantum mechanics to generate true random numbers.This scheme for generating random numbers is called Quantum Random Number Generator(QRNG).In the QRNG protocol,the Semi-deviceindependent Quantum Random Number Generator(SDI-QRNG)is widely used because it only needs to make simple assumptions about the device to achieve better random number performance.However,almost all the SDI-QRNG protocols have assumed to employ single-photon sources to generate quantum random numbers.As we know,the ideal single-photon source unfortunately does not exist under current technology,and this may become a bottleneck for the practical application of quantum random numbers.This paper mainly studies practical semi-device-independent quantum random number generator with practical sources,mainly including the following contents:1.Practical decoy-state quantum random number generator with weak coherent sources.We mainly study practical decoy-state quantum random number generator with weak coherent sources(WCS),which uses decoy-state method to generate random numbers.We employ three different intensities to precisely estimate the upper and lower bounds of effective single-photon events and then extract out real quantum random numbers.2.Measurement-device-independent quantum random-number generation with a heralded single-photon source.We mainly study the measurement-device-independent quantum randomnumber generation with heralded single-photon sources(HSPSs),we assume that the measurement device is untrusted and consider the influence of statistical fluctuation.Simulation results show that this scheme has higher loss tolerance than the scheme of using weak coherent light sources.3.In the two new semi-device-independent quantum random number generators mentioned in this article,this article will consider the fact that only a limited number of pulses can be sent in practice,that is,the influence of the finite length effect on the extractable randomness.The core idea is to obtain as much randomness as possible by optimizing parameter values related to the magnitude of randomness.