The generation of 68 Gbps quantum random number by measuring laser phase fluctuations

Nie, You-Qi; Huang, Le Hui; Liu, Yang; Payne, F.P.; Zhang, Jun; Pan, Jian-Wei

doi:10.1063/1.4922417

Cited by 131 publications

(97 citation statements)

References 23 publications

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“…The output value x i+k includes the parity of k raw bits, di+1 to d i+k , due to pulses spacelike separated from the distant measurement and from the entanglement production. optical phase within the laser [30,31], and, thus, the relative phase φ from one pulse to the next. At the time a pulse leaves the laser, it is already a macroscopic (∼ mW) signal, with a phase that has been fully randomized by the microscopic process of spontaneous emission.…”

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confidence: 99%

Generation of Fresh and Pure Random Numbers for Loophole-Free Bell Tests

et al. 2015

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We demonstrate extraction of randomness from spontaneous-emission events less than 36 ns in the past, giving output bits with excess predictability below 10 −5 and strong metrological randomness assurances. This randomness generation strategy satisfies the stringent requirements for unpredictable basis choices in current "loophole-free Bell tests" of local realism [Hensen et al., Nature (London) 526, 682 (2015); Giustina et al., Phys. Rev. Lett. 115, 250401 (2015); Shalm et al., Phys. Rev. Lett. 115, 250402 (2015)].PACS numbers: 03.65.Ud, 03.65.Ta, 42.50.Ct, Quantum nonlocality [1] is one of the most striking predictions to emerge from quantum theory. Beyond their fundamental interest, loophole-free Bell tests enable powerful "device independent" information protocols, guaranteed by the impossibility of faster-than-light communication [2]. Bell tests and device-independent protocols employ spacelike separation of measurements to guarantee the nonlocality of correlations [3][4][5][6][7][8] and the monogamy of correlations under the no-signaling principle [9][10][11]. To be secure, they must close two spacetime loopholes: no basis choice may influence a distant particle (locality loophole), and the entanglement generation must not influence the basis choices (freedom-ofchoice loophole). Current efforts [6,7,[12][13][14] to simultaneously close the detection [4,6,7], locality [3], and freedom-of-choice (FoC) [5,8] loopholes require random number generators (RNGs) with an unprecedented combination of speed, unpredictability, and confidence [15][16][17].Here we combine ultrafast RNG by accelerated laser phase diffusion [18][19][20] with real-time randomness extraction and metrological randomness assurances [21] to produce a RNGs suitable for loophole-free Bell tests. Because the laser phase diffusion is driven by effects, including spontaneous emission, that are unpredictable both in quantum theory and in an important class of stochastic hidden variable theories, the source can be used to address the "freedom-of-choice" loophole [22]. Using a detailed and validated model of the signal generation process, we show the effectiveness of parity-bit randomness extraction of this source. Under paranoid assumptions, we infer excess predictability below 10 −5 at 6σ statistical confidence for output based on phase-diffusion events less than 36 ns old. A statistical analysis based on 2.3 Tbits of random data supports the metrological assessment of extreme unpredictability. The results enable definitive nonlocality experiments and secure communications without the need for trusted devices [9,11,23,24].As shown in Fig. 1, the locality and freedom-of-choice loopholes can be closed by spacelike separation of the random events that determine the basis choice from the distant detection and from the production of the pairs of particles, respectively [10]. This requires generation of randomness in a time window shorter than the light time between the detectors. Closing the "detection loophole" requires high efficiency and motivates p...

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confidence: 99%

Generation of Fresh and Pure Random Numbers for Loophole-Free Bell Tests

et al. 2015

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“…To further increase the rate, one straightforward way is to use a detector with a larger bandwidth. For example, using a 15GHz detector, the sampling rate can reach 10 Giga samples per second (GSps) [14]. The corresponding random number generation rate could be 51.2 Gbps.…”

Section: Fig 2: Histogram Of the Measurement Results And Amentioning

confidence: 99%

“…Furthermore, the raw output of the detector may not be uniformly distributed. The second step in random number generation is to perform randomness extraction to generate uniformly distributed random numbers uncorrelated to the untrusted technical noises [7][8][9][10][11][12][13][14]. In practice, to conduct randomness extraction effectively, the quantum noise should be dominant over the technical noises.…”

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confidence: 99%

True randomness from an incoherent source

2017

Review of Scientific Instruments

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Quantum random number generators (QRNGs) harness the intrinsic randomness in measurement processes: the measurement outputs are truly random given the input state is a superposition of the eigenstates of the measurement operators. In the case of trusted devices, true randomness could be generated from a mixed state ρ so long as the system entangled with ρ is well protected. We propose a random number generation scheme based on measuring the quadrature fluctuations of a single mode thermal state using an optical homodyne detector. By mixing the output of a broadband amplified spontaneous emission (ASE) source with a single mode local oscillator (LO) at a beam splitter and performing differential photo-detection, we can selectively detect the quadrature fluctuation of a single mode output of the ASE source, thanks to the filtering function of the LO. Experimentally, a quadrature variance about three orders of magnitude larger than the vacuum noise has been observed, suggesting this scheme can tolerate much higher detector noise in comparison with QRNGs based on measuring the vacuum noise. The high quality of this entropy source is evidenced by the small correlation coefficients of the acquired data. A Toeplitz hashing extractor is applied to generate unbiased random bits from the Gaussian distributed raw data, achieving an efficiency of 5.12 bits per sample. The output of the Toeplitz extractor successfully passes all the NIST statistical tests for random numbers. Truly random numbers are required in many branches of science and technology, from fundamental research in quantum mechanics [1] to practical applications such as cryptography [2]. While a pseudorandom number generator can expand a short random seed into a long train of apparent "random" bits using deterministic algorithms, the entropy of generated random numbers is still bounded by the original short random seed. To generate true randomness, researchers have been exploring various physical processes.Quantum random number generation is an emerging technology [3,4], which can provide high-quality random numbers with proven randomness. Different from physical random number generators exploring chaotic behaviors of classical systems, a quantum random number generator (QRNG) harnesses the truly probabilistic nature of fundamental quantum processes [5,6].In general, the process of random number generation can be divided into two steps: the measurement step and the randomness extraction step. In the first * qib1@ornl.gov a

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“…This phase-stabilisation scheme has been adopted in a ≥ 6 Gbps QRNG 42 and a 68-Gbps QRNG demonstration. 45 Phase noise-based QRNG has also been implemented using a pulsed laser source, in which the phase difference between adjacent pulses is automatically randomised. 41,43,44 A speed of 80 Gbps (raw rate as shown in Table 1) has been demonstrated.…”

Section: Vacuum Noisementioning

confidence: 99%

“…Amplified spontaneous emission To overcome the bandwidth limitation of shot noise-limited homodyne detection, researchers have developed QRNGs based on measuring phase [40][41][42][43][44][45] or intensity noise 46,47 of amplified spontaneous emission(ASE), which is quantum mechanical by nature. 15,48,49 In the phase noise-based QRNG scheme, random numbers are generated by measuring a field quadrature of phase-randomised weak coherent states (signal states).…”

Section: Vacuum Noisementioning

confidence: 99%

Quantum random number generation

Ma¹,

Yuan²,

Cao³

et al. 2016

npj Quantum Inf

317

215

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Quantum physics can be exploited to generate true random numbers, which have important roles in many applications, especially in cryptography. Genuine randomness from the measurement of a quantum system reveals the inherent nature of quantumnesscoherence, an important feature that differentiates quantum mechanics from classical physics. The generation of genuine randomness is generally considered impossible with only classical means. On the basis of the degree of trustworthiness on devices, quantum random number generators (QRNGs) can be grouped into three categories. The first category, practical QRNG, is built on fully trusted and calibrated devices and typically can generate randomness at a high speed by properly modelling the devices. The second category is self-testing QRNG, in which verifiable randomness can be generated without trusting the actual implementation. The third category, semi-self-testing QRNG, is an intermediate category that provides a tradeoff between the trustworthiness on the device and the random number generation speed.

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The generation of 68 Gbps quantum random number by measuring laser phase fluctuations

Cited by 131 publications

References 23 publications

Generation of Fresh and Pure Random Numbers for Loophole-Free Bell Tests

Generation of Fresh and Pure Random Numbers for Loophole-Free Bell Tests

True randomness from an incoherent source

Quantum random number generation

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