Calibration Of Quantum Noise Power Spectrum For Metrological Standard Quantum Random Numbers

Random number fundamentally determines the security of information system and plays a vital role in the field of global communication security and financial security.The generation of quantum random numbers is based on the uncertain nature of quantum physics,namely the intrinsic randomness of quantum,which is a true random number generation scheme that can be proved by security information theory.Among all kinds of quantum random number generation schemes,the quantum random number generator(QRNG)based on continuousvariable(cv)quantum state quadrature fluctuations has particular application prospect because of its merits of explicit entropy source and measurement model,high detection bandwidth and robustness.For the actual quantum random number generation,the strict evaluation of the quantum entropy content of the system,the extraction of quantum random number and the effective elimination of edge information are the guarantee of the security of the generated quantum random numbers.In the cv quantum random number generation scheme,the homodyne system can suppress the classical common mode noise and amplify the quadrature fluctuations of the cv quantum state to the macroscopic level based on its local gain and electronic gain,and then generate the quantum random numbers by digitization.However,in the actual process,laser intensity noise,non-ideal factors in detection and analog-to-digital conversion will all introduce side-information to the cv quantum random numbers,which is inevitable in the generation process of quantum random number.In the previous schemes of cv QRNG,the homodyne detection and photocurrent signal quantization were dealt partially ideally.And the confirmation of the measured is quantum quadrature fluctuation was determined only by the linearly enhancement of the local.Our research is oriented towards cv QRNG with metrological standard,specifically,our work focus on the strict calibration of quantum noise power spectrum during the generation of cv quantum random number.Without idealized assumptions on any step,and by measuring transfer function of the system,noise power spectrum in quantum state detection is calibrated in the frequency domain.The transfer function includes the excessive noise caused by non-ideal system factors such as local laser intensity noise,non-ideal balance of beam splitter,finite CMRR,quantum efficiency of diodes and ADC input/output coupling.The work completed at present includes the following aspects:Firstly,the generation and extraction of vacuum state based cv quantum random number,the influence of homodyne detection gain on the quantum noise entropy content of the system and the influence of side-information caused by electronic noise in the quantification of random variable were studied experimentally.The quantification model of the min-entropy of the quantum random number generation system was established.Second,beat signal is applied to detect the transfer function of a frequency node within the homodyne bandwidth.Based on the time domain signals output from the final ADC of the quantum random number generation system,power spectrum of the beat node is reconstructed based on the average period diagram,and the optimal window function and segment rule of the average period diagram are determined.Thirdly,by controlling the frequency of probe beam,the system's input-output functions at each beat-node frequency within the detecting bandwidth of homodyne are scanned.At each frequency node,power spectrum is reconstructed from respective time sequence signal.Finally,the power spectrum of the output signal of the system detected by the spectral analyzer is calibrated according to the reconstructed power spectrum.The rigorous calibration of the noise power spectrum of quantum state detection during the generation of cv quantum random number is preliminarily realized.This work is oriented to the metrology-grade evaluation of the cv QRNG.Based on the strict calibration of the noise power spectrum from entropy source measurement,the confidence interval can be given with the measurement uncertainty,so as to seek the high entropy and high speed quantum random number extraction scheme under the constraint of the metrological standard.The rigorous calibration based on the excessive noise of the power spectrum of the entropy source lays a foundation for the metrology-grade evaluation of the safety of cv QRNG.