We demonstrate a high bit-rate quantum random number generator by interferometric detection of phase diffusion in a gain-switched DFB laser diode. Gain switching at few-GHz frequencies produces a train of bright pulses with nearly equal amplitudes and random phases. An unbalanced Mach-Zehnder interferometer is used to interfere subsequent pulses and thereby generate strong random-amplitude pulses, which are detected and digitized to produce a high-rate random bit string. Using established models of semiconductor laser field dynamics, we predict a regime of high visibility interference and nearly complete vacuum-fluctuation-induced phase diffusion between pulses. These are confirmed by measurement of pulse power statistics at the output of the interferometer. Using a 5.825 GHz excitation rate and 14-bit digitization, we observe 43 Gbps quantum randomness generation.

Ultra-fast quantum randomness generation by accelerated phase diffusion in a pulsed laser diode.

Inducible transgene expression provides a useful tool to analyze gene function. The moss Physcomitrellapatens is a model basal land plant with well-developed research tools, including a high efficiency of gene targeting and substantial genomics resources. However, current systems for controlled transgene expression remain limited. Here we report the development of an estrogen receptor mediated inducible gene expression system, based on the system used in flowering plants. After identifying the appropriate promoters to drive the chimeric transducer, we succeeded in inducing transcription over 1,000-fold after 24 h incubation with β-estradiol. The P. patens system was also effective for high-level long-term induction of gene expression; transcript levels of the activated gene were maintained for at least seven days on medium containing β-estradiol. We also established two potentially neutral targeting sites and a set of vectors for reproducible expression of two transgenes. This β-estradiol-dependent system will be useful to test genes individually or in combination, allowing stable, inducible transgenic expression in P. patens.

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System for Stable β-Estradiol-Inducible Gene Expression in the Moss Physcomitrella patens

(2002). What Is a Random Sequence? The American Mathematical Monthly: Vol. 109, No. 1, pp. 46-63.

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What Is a Random Sequence

In this paper, a nondeterministic random number generator based on detection of the single photons emitted by an Si-CMOS-LED light source integrated for the first time on the detector chip is presented and experimentally demonstrated. We use a ring-shaped single-photon avalanche diode (SPAD) around the Si-CMOS-LED fabricated in 0.35-μm HV-CMOS technology to generate random events. The time intervals between single-photon events are independent quantum random variables. A field-programmable gate array (FPGA) digitizes the time variables to the stream of random bits. Bias in the raw data due to the nonuniform distribution of the time intervals is removed by postprocessing in a special configuration of xor gates to improve the randomness of the generated random bits. The quantum random numbers in 1-Gb streams with bit generation rate of 1 Mb/s were directly delivered to a personal computer (PC) and passed all statistical tests from ENT, STS, and DIEHARD, as well as for more accuracy correlation and bias tests applied on these streams.

A Monolithic Silicon Quantum Random Number Generator Based on Measurement of Photon Detection Time

The key point of cryptography is cryptographic algorithms and keys. The random number generator is used to generate seeds and keys randomly in many cryptographic systems. For this reason, it is essential to use keys to encrypt and decrypt the transferring information, and the security of these keys is closely related to the security of 5G network. We propose a true random number generator (TRNG) method in this paper, and are using visible spectrum for noise source. We consider that if the cryptography system utilizes data of visible spectrum using the proposed TRNG, and the TRNG generates random numbers with high entropy.

TRNG (True Random Number Generator) Method Using Visible Spectrum for Secure Communication on 5G Network

A new method of generating random digits using radiations from radioactive nuclide is described. The digits are stored on magnetic tape which allows repeated use if required. One hundred million such digits have been subjected to stringent tests for randomness. These tests, some of which are described, show that the random digits avoid the well‐documented defects of digits generated by arithmetic means. They perform well for applications where sequences of independent random digits are required.

Random Numbers Generated by a Physical Device

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Physical random numbers generated by radioactivity

We have developed a physical random number generator in which radioactivity, i.e., one of the most random phenomena, is used. The long-lived radioactive nuclide 241 Am and a clock pulse generator are used for generating random pulses and regular pulses, respectively. A 1024 channel scaler counts clock pulses between two consecutive random pulses. This procedure is repeated and the counts are stored in a computer. The last digit of a count at the scaler gives a digit of uniform physical random number. We have tested our random numbers for randomness and uniformity, and stored 600 million random digits on each compact disc for users.

H. Inoue

Papers

Random Numbers Generated by a Physical Device

Physical random numbers generated by radioactivity

Physical Random Numbers Generated by Radioactivity