A simple low-latency real-time certifiable quantum random number generator

Yanbao Zhang,Hiroki Takesue,William J Munro,Alan Mink,Takuya Ikuta,Hsin-Pin Lo,Toshimori Honjo

doi:10.1038/s41467-021-21069-8

Yanbao Zhang, Hiroki Takesue + Show 5 more

Open Access

https://doi.org/10.1038/s41467-021-21069-8

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Abstract

Quantum random numbers distinguish themselves from others by their intrinsic unpredictability arising from the principles of quantum mechanics. As such they are extremely useful in many scientific and real-world applications with considerable efforts going into their realizations. Most demonstrations focus on high asymptotic generation rates. For this goal, a large number of repeated trials are required to accumulate a significant store of certifiable randomness, resulting in a high latency between the initial request and the delivery of the requested random bits. Here we demonstrate low-latency real-time certifiable randomness generation from measurements on photonic time-bin states. For this, we develop methods to certify randomness taking into account adversarial imperfections in both the state preparation and the measurement apparatus. Every 0.12 s we generate a block of 8192 random bits which are certifiable against all quantum adversaries with an error bounded by 2−64. Our quantum random number generator is thus well suited for realizing a continuously-operating, high-security and high-speed quantum randomness beacon.

Highlights

Quantum random numbers distinguish themselves from others by their intrinsic unpredictability arising from the principles of quantum mechanics
We experimentally demonstrate that every 0.1 s a sufficient amount of entropy with respect to the quantum side information of Eve is certified such that a block of 8192 random bits is generated with a certified error bounded by 2−64 and with an extraction time of 0.02 s
We first introduce the setup of the problem and the main idea of our method for certifying randomness with the adversarial imperfections discussed above

Summary

Introduction

Quantum random numbers distinguish themselves from others by their intrinsic unpredictability arising from the principles of quantum mechanics. Its proper working and certifiability rely on the trust of both the quantum state prepared and the measurement performed This scheme is device-dependent[2,3]. In this work we explore a simple practical scheme for the realization of a low-latency real-time certifiable quantum random number generator (QRNG). The simple scheme works ideally as follows: At each trial a horizontally polarized single photon is emitted from a source, and measured randomly along either the X-basis (diagonal/anti-diagonal polarization basis) to generate a random bit or the Z-basis (horizontal/vertical polarization basis) to verify the prepared state. We emphasize that except the above bounds which characterize the adversarial imperfections, our method does not need any other information about the state prepared or measurements performed In this sense, our QRNG works in a semi-device-independent way. We experimentally demonstrate that every 0.1 s a sufficient amount of entropy with respect to the quantum (or classical) side information of Eve is certified such that a block of 8192 (or 2 × 8192) random bits is generated with a certified error bounded by 2−64 and with an extraction time of 0.02 s

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