Unconventional, special-purpose machines may aid in accelerating the solution of some of the hardest problems in computing, such as large-scale combinatorial optimizations, by exploiting different operating mechanisms than those of standard digital computers. We present a scalable optical processor with electronic feedback that can be realized at large scale with room-temperature technology. Our prototype machine is able to find exact solutions of, or sample good approximate solutions to, a variety of hard instances of Ising problems with up to 100 spins and 10,000 spin-spin connections.

/pdf/a-fully-programmable-100-spin-coherent-ising-machine-with-inaxlu4ff3.pdf

A fully programmable 100-spin coherent Ising machine with all-to-all connections

Crystalline lithium niobate (LN) is an important optical material because of its broad transmission window that spans from ultraviolet to mid-infrared and its large nonlinear and electro-optic coefficients. Furthermore, the recent development and commercialization of LN-on-insulator (LNOI) technology has opened an avenue for the realization of integrated on-chip photonic devices with unprecedented performances in terms of propagation loss, optical nonlinearity, and electro-optic tunability. This review begins with a brief introduction of the history and current status of LNOI photonics. We then discuss the fabrication techniques of LNOI-based photonic structures and devices. The recent revolution in the LN photonic industry has been sparked and is still being powered by innovations of the nanofabrication technology of LNOI, which enables the production of building block structures, such as optical microresonators and waveguides of unprecedented optical qualities. The following sections present various on-chip LNOI devices categorized into nonlinear photonic and electro-optic tunable devices and photonic-integrated circuits. Some conclusions and future perspectives are provided.

/pdf/advances-in-on-chip-photonic-devices-based-on-lithium-461c9g3pmy.pdf

Advances in on-chip photonic devices based on lithium niobate on insulator

Randomness is far from a disturbing disorder in nature. Rather, it underlies many processes and functions. Randomness can be used to improve the efficacy of development and of systems under certain conditions. Moreover, valid unpredictable random-number generators are needed for secure communication, rendering predictable pseudorandom strings unsuitable. This paper reviews methods of generating randomness in various fields. The potential use of these methods is also discussed. It is suggested that by disordering a “false order,” an effective disorder can be generated to improve the function of systems.

/pdf/generating-randomness-making-the-most-out-of-disordering-a-3u6cm1zpqs.pdf

Generating randomness: making the most out of disordering a false order into a real one.

Lithium niobate on insulator (LNOI), by taking advantage of versatile properties of lithium niobate (LN) and a large refractive index contrast, provides an ideal on-chip platform for studying a bro...

https://www.tandfonline.com/doi/pdf/10.1080/23746149.2021.1889402

Nonlinear wave mixing in lithium niobate thin film

Abstract. Photonics on thin-film lithium niobate (TFLN) has emerged as one of the most pursued disciplines within integrated optics. Ultracompact and low-loss optical waveguides and related devices on this modern material platform have rejuvenated the traditional and commercial applications of lithium niobate for optical modulators based on the electro-optic effect, as well as optical wavelength converters based on second-order nonlinear effects, e.g., second-harmonic, sum-, and difference-frequency generations. TFLN has also created vast opportunities for applications and integrated solutions for optical parametric amplification and oscillation, cascaded nonlinear effects, such as low-harmonic generation; third-order nonlinear effects, such as supercontinuum generation; optical frequency comb generation and stabilization; and nonclassical nonlinear effects, such as spontaneous parametric downconversion for quantum optics. Recent progress in nonlinear integrated photonics on TFLN for all these applications, their current trends, and future opportunities and challenges are reviewed.

https://www.spiedigitallibrary.org/journals/advanced-photonics/volume-4/issue-3/034001/Applications-of-thin-film-lithium-niobate-in-nonlinear-integrated-photonics/10.1117/1.AP.4.3.034001.pdf

Applications of thin-film lithium niobate in nonlinear integrated photonics

We demonstrate a viable source of unbiased quantum random numbers whose statistical properties can be arbitrarily programmed without the need for any postprocessing such as randomness distillation or distribution transformation It is based on measuring the arrival time of single photons in shaped temporal modes that are tailored with an electro-optical modulator We show that quantum random numbers can be created directly in customized probability distributions and pass all randomness tests of the NIST and Dieharder test suites without any randomness extraction The min-entropies of such generated random numbers are measured close to the theoretical limits, indicating their near-ideal statistics and ultrahigh purity Easy to implement and arbitrarily programmable, this technique can find versatile uses in a multitude of data analysis areas

Programmable quantum random number generator without postprocessing.

We demonstrate phase-sensitive amplification in periodically poled lithium niobate nanowavguides, achieving a net gain of 11.8 dB and an extinction ratio of 14.9 dB for 1.2-ps pump pulse with 2.4-pJ pulse energy.

Phase-Sensitive Amplification in Nanophotonic Periodically Poled Lithium Niobate Waveguides

A device for generation of genuine random numbers, uses quantum stochastic processes in optical parametric nonlinear media. The dimensionality of the random numbers is varied from 2 to over 100,000. Their statistical properties, including the correlation function amongst random numbers, are tailored using linear and nonlinear optical circuits following the parametric nonlinear media. Both the generation and manipulation of random numbers can be integrated on a single nanophotonics chip. By incorporating optoelectric effects, fast streams of random numbers can be created in custom statistical properties, which can be updated or reconfigured in real time, such as at 10 GHz speed. The unpredictability of the random numbers is quantifying by evaluating their min-entropy. The genuineness of quantum random numbers is tested using both statistical tools and independently verified by measuring the quantum entanglement between the photons in real time reducing vulnerability to hostile attack.

Chip-integrated device and methods for generating random numbers that is reconfigurable and provides genuineness verification

Random numbers are a fundamental and useful resource in science and engineering with important applications in simulation, machine learning and cyber-security. Quantum systems can produce true random numbers because of the inherent randomness at the core of quantum mechanics. As a consequence, quantum random number generators are an efficient method to generate random numbers on a large scale. We study in this paper the applications of a viable source of unbiased quantum random numbers (QRNs) whose statistical properties can be arbitrarily programmed without the need for any post-processing and that pass all standard randomness tests of the NIST and Dieharder test suites without any randomness extraction. Our method is based on measuring the arrival time of single photons in shaped temporal modes that are tailored with an electro-optical modulator. The advantages of our QRNs are shown via two applications: simulation of a fractional Brownian motion, which is a non-Markovian process, and option pricing under the fractional SABR model where the stochastic volatility process is assumed to be driven by a fractional Brownian motion. The results indicate that using the same number of random units, our QRNs achieve greater accuracy than those produced by standard pseudo-random number generators. Moreover, we demonstrate the advantages of our method via an increase in computational speed, efficiency, and convergence.

Quantum systems for Monte Carlo methods and applications to fractional stochastic processes

Quantum random number (QRNG) beacons distinguish themselves from classical counterparts by providing intrinsic unpredictability originating from the fundamental laws of quantum mechanics. Most demonstrations have focused on certifiable randomness generators to guarantee the public that their genuineness is independent from imperfect implementations. These efforts however do not benefit applications where multiple distrusted users need a common set of random numbers, as they must rely on the honesty of beacon owners. In this paper, we formally introduce a design and proof-of-principle experiment of the first consensus protocol producing QRNs in a decentralized environment (dQRNG). Such protocol allows N number of participants contribute in the generation process and publicly verify numbers they collect. Security of the protocol is guaranteed given(N-1) dishonest participants. Our method is thus suited for distribute systems that requires a bias-resistant, highly secure, and public-verifiable random beacon.

Lac Nguyen

Papers

Programmable quantum random number generator without postprocessing.

Phase-Sensitive Amplification in Nanophotonic Periodically Poled Lithium Niobate Waveguides

Chip-integrated device and methods for generating random numbers that is reconfigurable and provides genuineness verification

Quantum systems for Monte Carlo methods and applications to fractional stochastic processes

A trustless decentralized protocol for distributed consensus of public quantum random numbers.