Configurable Array Research Articles

Robust Teleportation of a Surface Code and Cascade of Topological Quantum Phase Transitions

Teleportation is a facet where quantum measurements can act as a powerful resource in quantum physics, as local measurements allow us to steer quantum information in a nonlocal way. While this has long been established for a single Bell pair, the teleportation of a many-qubit entangled state using nonmaximally entangled resources presents a fundamentally different challenge. Here, we investigate a tangible protocol for teleporting a long-range entangled surface-code state using elementary Bell measurements and its stability in the presence of coherent errors that weaken the Bell entanglement. We relate the underlying threshold problem to the physics of anyon condensation under weak measurements and map it to a variant of the Ashkin-Teller model of statistical mechanics with Nishimori-type disorder, which gives rise to a cascade of phase transitions. Tuning the angle of the local Bell measurements, we find a continuously varying threshold. Notably, the threshold moves to infinity for the X+Z angle along the self-dual line—indicating that infinitesimally weak entanglement is sufficient in teleporting a self-dual topological surface code. Our teleportation protocol, which can be readily implemented in dynamically configurable Rydberg-atom arrays, thereby gives guidance for a practical demonstration of the power of quantum measurements. Published by the American Physical Society 2024

High-throughput systolic array-based accelerator for hybrid transformer-CNN networks

In this era of Transformers enjoying remarkable success, Convolutional Neural Networks (CNNs) remain highly relevant and useful. Indeed, hybrid Transformer-CNN network architectures, which combine the benefits of both approaches, have achieved impressive results. Vision Transformer (ViT) is a significant neural network architecture that features a convolutional layer as its first layer, primarily built on the transformer framework. However, owing to the distinct computation patterns inherent in attention and convolution, existing hardware accelerators for these two models are typically designed separately and lack a unified approach toward accelerating both models efficiently. In this paper, we present a dedicated accelerator on a field-programmable gate array (FPGA) platform. The accelerator, which integrates a configurable three-dimensional systolic array, is specifically designed to accelerate the inferential capabilities of hybrid Transformer-CNN networks. The Convolution and Transformer computations can be mapped to a systolic array by unifying these operations for matrix multiplication. Softmax and LayerNorm which are frequently used in hybrid Transformer-CNN networks were also implemented on FPGA boards. The accelerator achieved high performance with a peak throughput of 722 GOP/s at an average energy efficiency of 53 GOPS/W. Its respective computation latencies were 51.3 ms, 18.1 ms, and 6.8 ms for ViT-Base, ViT-Small, and ViT-Tiny. The accelerator provided a 12× improvement in energy efficiency compared to the CPU, a 2.3× improvement compared to the GPU, and a 1.5× to 2× improvement compared to existing accelerators regarding speed and energy efficiency.

Dynamic Electric Discharge Paths in Liquid Metal Marble Arrays.

Electric discharge occurs ubiquitously in both natural and engineered systems, where the discharge paths provide critical information. However, control and visualization of discharge patterns is a challenging task. Here arrays of liquid metal marbles, droplets of a gallium-indium eutectic alloy with a copper-doped ZnS luminescent coating, are designed for pixelated visualization of electric discharge paths at optical imaging length-scales. The ZnS particles embed themselves into the surface of liquid metal droplets and are anchored by a self-limiting gallium oxide layer. The operation is achieved by generating spark discharges at inter-marble air gaps and reduced voltage drop across highly conducting liquid metal droplets. By taking advantage of the malleability of soft liquid metal marbles, the dynamic visualization platforms allow the manipulation of discharge path selections in configurable marble arrays and the embedding of artificial defect features. The systems are further integrated for characterizing dynamic changes in granular and soft systems, and for enabling logic computing and information encoded display. This demonstration holds promises for creating new-generation electric discharge-based optoelectronics.

A Configurable 64-Channel ASIC for Cherenkov Radiation Detection from Space

This work presents the development of a 64-channel application-specific integrated circuit (ASIC), implemented to detect the optical Cherenkov light from sub-orbital and orbital altitudes. These kinds of signals are generated by ultra-high energy cosmic rays (UHECRs) and cosmic neutrinos (CNs). The purpose of this front-end electronics is to provide a readout unit for a matrix of silicon photo-multipliers (SiPMs) to identify extensive air showers (EASs). Each event can be stored into a configurable array of 256 cells where the on-board digitization can take place with a programmable 12-bits Wilkinson analog-to-digital converter (ADC). The sampling, the conversion process, and the main digital logic of the ASIC run at 200 MHz, while the readout is managed by dedicated serializers operating at 400 MHz in double data rate (DDR). The chip is designed in a commercial 65 nm CMOS technology, ensuring a high configurability by selecting the partition of the channels, the resolution in the interval 8–12 bits, and the source of its trigger. The production and testing of the ASIC is planned for the forthcoming months.

Distributed quantum sensing with squeezed-vacuum light in a configurable array of Mach-Zehnder interferometers

Distributed quantum sensing with squeezed-vacuum light in a configurable array of Mach-Zehnder interferometers

Chip-to-Chip Interfaces for Large-Scale Highly Configurable mmWave Phased Arrays

This article presents a chip-to-chip (C2C) interface for constructing reconfigurable phased arrays to be used in fifth-generation (5G)/sixth-generation (6G) wireless systems. The C2C interface further facilitates building phased array panels by allowing the use of grid-based PCB routing, thus providing flexibility in the system design. An eight-element RFIC capable of handling two independent data-streams is fabricated using 45-nm CMOS technology. The RFIC incorporates four C2C interfaces operating at 27 GHz, two C2C interfaces operating at 9 GHz, and a complex baseband (BB) with single-sided bandwidth in excess of 400 MHz. The architecture is tested by flip-chip bonding two fabricated RFICs on an eight-layer Megtron 7 PCB. In this article, only the receiver path of the RFIC and the phased array is described. Performance of both the single RFIC and the combination using the 27-GHz C2C interface is demonstrated using conductive and over-the-air (OTA) measurements. OTA measurements are conducted using 5GNR FR2 OFDM waveforms with a signal bandwidth of up to 800 MHz. The measured RF to BB conversion gain for a single element is larger than 23 dB and the minimum measured noise figure (NF) is 6.2 dB. The nominal dc power consumed by the receiver per element per stream is 116.5 mW. The RFIC occupies a normalized area per element per data stream of 2.7 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^2$</tex-math> </inline-formula> . The RFIC is capable of supporting dual-polarized antennas or in a large-scale panel utilizing the same antenna elements to two independently weighted data streams as part of the hybrid beamforming architecture.

All-in-One SPAD Ranging Sensor With Real-Time Xtalk Calibration and Integrated Biasing

This letter presents a novel fully integrated dToF system-on-chip ranging sensor based on a SPADs array. The sensor is made a configurable array of 16 × 16 SPADs, a 940nm VCSEL, a co-design VCSEL driver and embedded DSP core. To suitable different ranging scenarios with high reliability and low cost, the above mentioned are all packaged into one module for ranging. However, the package of coverglass can cause Xtalk, which have a negative impact on ranging. In order to reduce the influence of Xtalk on ranging. This letter proposes a real-time Xtalk calibration circuit system, which can automatically adjust the laser pulse width, when Xtalk and target bins are mixed together. And also to mitigate the effect of SPAD jitter on the Xtalk bins width, an adjustable bias voltage charge pump circuit is adopted to realize the accurate adjustment of pixel SPAD’s bias voltage. The system has been turned out with precision of better than 5mm within 6m in 80% reflectance of target, still with a precision better than 8mm at a distance within 4m in 18% reflectance of target.

A dToF Ranging Sensor with Accurate Photon Detector Measurements for LiDAR Applications.

Direct time-of-flight (dToF) ranging sensors based on single-photon avalanche diodes (SPADs) have been used as a prominent depth-sensing devices. Time-to-digital converters (TDCs) and histogram builders have become the standard for dToF sensors. However, one of the main current issues is the bin width of the histogram, which limits the accuracy of depth without TDC architecture modifications. SPAD-based light detection and ranging (LiDAR) systems require new methods to overcome their inherent drawbacks for accurate 3D ranging. In this work, we report an optimal matched filter to process the raw data of the histogram to obtain high-accuracy depth. This method is performed by feeding the raw data of the histogram into the different matched filters and using the Center-of-Mass (CoM) algorithm for depth extraction. Comparing the measurement results of different matched filters, the filter with the highest depth accuracy can be obtained. Finally, we implemented a dToF system-on-chip (SoC) ranging sensor. The sensor is made of a configurable array of 16 × 16 SPADs, a 940 nm vertical-cavity surface-emitting laser (VCSEL), an integrated VCSEL driver, and an embedded microcontroller unit (MCU) core to implement the best matched filter. To achieve suitably high reliability and low cost, the above-mentioned features are all packaged into one module for ranging. The system resulted in a precision of better than 5 mm within 6 m with 80% reflectance of the target, and had a precision better than 8 mm at a distance within 4 m with 18% reflectance of the target.

Broadband Acoustic Metaveils for Configurable Camouflage

We theoretically propose and experimentally demonstrate acoustic metasurfaces that exhibit undistorted transmission and configurable reflection, therefore serving as remarkable veil structures with camouflage effects for sonars, hereby denoted as acoustic metaveils. The metaveil is composed of a configurable array of two acoustic meta-atoms, which are the flipped counterparts of each other. Reciprocity and space inversion guarantee distortion-free transmission in an ultrabroad spectrum, irrespective of the arrangement of the array, while the reflection can be conveniently manipulated by changing the arrangement to produce the desired acoustic camouflage. Three types of unusual reflection behaviors are demonstrated, including diffuse reflection, multibeam reflection, and reflective focusing. The acoustic metaveils open a way to independently manipulate the reflection without influencing the acoustic transmission wave front, which is a crucial step for sonar stealth and camouflage.

Design of Nupix-A1, a Monolithic Active Pixel Sensor for heavy-ion physics

A Monolithic Active Pixel Sensor (MAPS) named Nupix-A1 has been designed in a 130 nm process for the heavy-ion experiments at HIRFL and HIAF. The Nupix-A1 can simultaneously measure particle hits’ energy, arrival time, and position. The Nupix-A1 consists of 128 × 64 pixels with the size of 30μm×30μm. A configurable DAC array, which consists of four 10-bit voltage DACs and seven 8-bit current DACs, tunes the bias of the in-pixel circuit. The analog signal from the pixels in four adjacent columns is converted into a digital signal by an 11-bit column-parallel ADC. The digitized data is encoded, serialized, and transmitted by the 5 Gbps data transmission link. This paper will discuss the design of the Nupix-A1.

Configurable simulation strategies for testing pollutant plume source localization algorithms using autonomous multisensor mobile robots

In hazardous situations involving the dispersion of chemical, biological, radiological, and nuclear pollutants, timely containment of the emission is critical. A contaminant disperses as a dynamically evolving plume into the atmosphere, introducing complex difficulties in predicting the dispersion trajectory and potential evacuation sites. Strategies for predictive modeling of rapid contaminant dispersion demand localization of the emission source, a task performed effectively via unmanned mobile-sensing platforms. With vast possibilities in sensor configurations and source-seeking algorithms, platform deployment in real-world applications involves much uncertainty alongside opportunity. This work aims to develop a plume source detection simulator to offer a reliable comparison of source-seeking approaches and performance testing of ground-based mobile-sensing platform configurations prior to experimental field testing. Utilizing ROS, Gazebo, MATLAB, and Simulink, a virtual environment is developed for an unmanned ground vehicle with a configurable array of sensors capable of measuring plume dispersion model data mapped into the domain. For selected configurations, gradient-based and adaptive exploration algorithms were tested for source localization using Gaussian dispersion models in addition to large eddy simulation models incorporating the effects of atmospheric turbulence. A unique global search algorithm was developed to locate the true source with overall success allowing for further evaluation in field experiments. From the observations obtained in simulation, it is evident that source-seeking performance can improve drastically by designing algorithms for global exploration while incorporating measurements of meteorological parameters beyond solely concentration (e.g. wind velocity and vorticity) made possible by the inclusion of high-resolution large eddy simulation plume data.

Theoretical methods to design and test quantum simulators for the compact Abelian Higgs model

The lattice compact Abelian Higgs model is a non-perturbative regularized formulation of low-energy scalar quantum electrodynamics. In 1+1 dimensions, this model can be quantum simulated using a ladder-shaped optical lattice with Rydberg-dressed atoms (Zhang et al., Phys. Rev. Lett. 121, 223201). In this setup, one spatial dimension is used to carry the angular momentum of the quantum rotors. One can use truncations corresponding to spin-2 and spin-1 to build local Hilbert spaces associated with the links of the lattice. We argue that ladder-shaped configurable arrays of Rydberg atoms can be used for the same purpose. We make concrete proposals involving two and three Rydberg atoms to build one local spin-1 space (a qutrit). We show that the building blocks of the Hamiltonian calculations are models with one and two spins. We compare target and simulators using perturbative and numerical methods. The two-atom setup provides an easily controllable simulator of the one-spin model while the three-atom setup involves solving nonlinear equations. This could be tested with current technology. We argue that near-term technology could be used to quantum simulate models with two or more spins.

Clock model interpolation and symmetry breaking in O(2) models

Motivated by recent attempts to quantum simulate lattice models with continuous Abelian symmetries using discrete approximations, we define an extended-O(2) model by adding a $\gamma \cos(q\varphi)$ term to the ordinary O(2) model with angular values restricted to a $2\pi$ interval. In the $\gamma \rightarrow \infty$ limit, the model becomes an extended $q$-state clock model that reduces to the ordinary $q$-state clock model when $q$ is an integer and otherwise is a continuation of the clock model for noninteger $q$. By shifting the $2\pi$ integration interval, the number of angles selected can change discontinuously and two cases need to be considered. What we call case $1$ has one more angle than what we call case $2$. We investigate this class of clock models in two space-time dimensions using Monte Carlo and tensor renormalization group methods. Both the specific heat and the magnetic susceptibility show a double-peak structure for fractional $q$. In case $1$, the small-$\beta$ peak is associated with a crossover, and the large-$\beta$ peak is associated with an Ising critical point, while both peaks are crossovers in case $2$. When $q$ is close to an integer by an amount $\Delta q$ and the system is close to the small-$\beta$ Berezinskii-Kosterlitz-Thouless transition, the system has a magnetic susceptibility that scales as $\sim 1 / (\Delta q)^{1 - 1/\delta'}$ with $\delta'$ estimates consistent with the magnetic critical exponent $\delta = 15$. The crossover peak and the Ising critical point move to Berezinskii-Kosterlitz-Thouless transition points with the same power-law scaling. A phase diagram for this model in the $(\beta, q)$ plane is sketched. These results are possibly relevant for configurable Rydberg-atom arrays where the interpolations among phases with discrete symmetries can be achieved by varying continuously the distances among atoms and the detuning frequency.

Configurable Multi-directional Systolic Array Architecture for Convolutional Neural Networks

The systolic array architecture is one of the most popular choices for convolutional neural network hardware accelerators. The biggest advantage of the systolic array architecture is its simple and efficient design principle. Without complicated control and dataflow, hardware accelerators with the systolic array can calculate traditional convolution very efficiently. However, this advantage also brings new challenges to the systolic array. When computing special types of convolution, such as the small-scale convolution or depthwise convolution, the processing element (PE) utilization rate of the array decreases sharply. The main reason is that the simple architecture design limits the flexibility of the systolic array. In this article, we design a configurable multi-directional systolic array (CMSA) to address these issues. First, we added a data path to the systolic array. It allows users to split the systolic array through configuration to speed up the calculation of small-scale convolution. Second, we redesigned the PE unit so that the array has multiple data transmission modes and dataflow strategies. This allows users to switch the dataflow of the PE array to speed up the calculation of depthwise convolution. In addition, unlike other works, we only make a few changes and modifications to the existing systolic array architecture. It avoids additional hardware overheads and can be easily deployed in application scenarios that require small systolic arrays such as mobile terminals. Based on our evaluation, CMSA can increase the PE utilization rate by up to 1.6 times compared to the typical systolic array when running the last layers of ResNet-18. When running depthwise convolution in MobileNet, CMSA can increase the utilization rate by up to 14.8 times. At the same time, CMSA and the traditional systolic arrays are similar in area and energy consumption.

Multifunctional Digital Backend for Quasar VLBI network

The new 13-meters radio telescope recently built at Svetloe observatory (Russia) required a backend device that could digitize wideband signals from the receiving system, process the signal appropriately, prepare and transmit the resulting signal to the recorder. The previously existing backends, also used at other radio telescopes of Quasar VLBI network, could not provide compatibility with VGOS (VLBI Global Observing System) requirements. We developed Multifunctional Digital Backend (MDBE) with superior performance, flexibility and functions to equip the new antenna and other radio telescopes of the network with the same backend compatible with both domestic and international systems. The MDBE contains up to 12 input channels with 2 GHz bandwidth, powerful and remotely configurable Field programmable gate arrays (FPGA) for digital signal processing, and optical transceivers with total throughput of 50 Gbps per channel. The digital downconverters implemented in FPGA can form sub channels with 0.5, 2, 4, 8, 16, and 32 MHz bandwidth freely tuned with 10 kHz step. In wideband mode a single channel with 512, 1024 or full 2048 MHz bandwidth can be recorded. The MDBE also supports single-dish applications, such as radiometric and spectrometric observations. The paper presents the results of hardware and firmware development of the system, and the experimental results received with the MDBE in Svetloe observatory.

Raman sideband cooling in optical tweezer arrays for Rydberg dressing

Single neutral atoms trapped in optical tweezers and laser-coupled to Rydberg states provide a fast and flexible platform to generate configurable atomic arrays for quantum simulation. The platform is especially suited to study quantum spin systems in various geometries. However, for experiments requiring continuous trapping, inhomogeneous light shifts induced by the trapping potential and temperature broadening impose severe limitations. Here we show how Raman sideband cooling allows one to overcome those limitations, thus, preparing the stage for Rydberg dressing in tweezer arrays.

UltraTrail: A Configurable Ultralow-Power TC-ResNet AI Accelerator for Efficient Keyword Spotting

Recent advances in machine learning show the superior behavior of temporal convolutional networks (TCNs) and especially their combination with residual networks (TC-ResNet) for intelligent sensor signal processing in comparison to classical CNNs and LSTMs. In this article, we propose UltraTrail, a configurable, ultralow-power TC-ResNet AI accelerator for sensor signal processing and its application to efficient keyword spotting (KWS). Following a strict hardware/model co-design approach, we have derived an optimized low-power hardware architecture for generalized TC-ResNet topologies consisting of a configurable array of processing elements and a distributed memory with dynamic content reallocation. We additionally extend the network with conditional computing to reduce the number of operations during inference and to provide the possibility for power-gating. The final accelerator implementation in Globalfoundries' 22FDX technology achieves a power consumption of 8.2 μW for the task of always-on KWS meeting the real-time requirement of 100 ms per inference with an accuracy of 93% on the Google Speech Command Dataset.

A new 1-bit configurable phase array antenna based on ‘ancient coin-like’ metasurface

Due to the low price, high efficiency and flexible manipulations, the metasurface has attracted more attentions. This paper proposes a new 1-bit configurable reflection array antenna with 11*11 unit cells. The unit cell in the metasurface, which is integrated with one PIN diode, shaped as ‘ancient coin’ can generate reflection phases between 165°-195° (180°±15°). The new phase array antenna can realize flexible manipulations to EM (electromagnetic) waves.

Emerging Two-Dimensional Gauge Theories in Rydberg Configurable Arrays

Solving strongly coupled gauge theories in two or three spatial dimensions is of fundamental importance in several areas of physics ranging from high-energy physics to condensed matter. On a lattice, gauge invariance and gauge-invariant (plaquette) interactions involve (at least) four-body interactions that are challenging to realize. Here, we show that Rydberg atoms in configurable arrays realized in current tweezer experiments are the natural platform to realize scalable simulators of the Rokhsar-Kivelson Hamiltonian—a 2D U(1) lattice gauge theory that describes quantum dimer and spin-ice dynamics. Using an electromagnetic duality, we implement the plaquette interactions as Rabi oscillations subject to Rydberg blockade. Remarkably, we show that by controlling the atom arrangement in the array we can engineer anisotropic interactions and generalized blockade conditions for spins built of atom pairs. We describe how to prepare the resonating valence bond and the crystal phases of the Rokhsar-Kivelson Hamiltonian adiabatically and probe them and their quench dynamics by on-site measurements of their quantum correlations. We discuss the potential applications of our Rydberg simulator to lattice gauge theory and exotic spin models.Received 25 July 2019Revised 20 February 2020Accepted 20 April 2020DOI:https://doi.org/10.1103/PhysRevX.10.021057Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasCoherent controlExotic phases of matterLattice gauge theoryQuantum simulationSpin icePhysical SystemsQuantum spin modelsRydberg atoms & moleculesTechniquesDualityOptical tweezersGeneral PhysicsInterdisciplinary PhysicsCondensed Matter & Materials PhysicsAtomic, Molecular & Optical

Toward Secured FPGA: Silicon Proven CLB With Reduced Information Leakage

The ubiquity of FPGAs in security applications makes it imperative to design a secured configurable logic block (sCLB) that is resilient to side channel attacks. In this letter, we take a step toward secured FPGA by introducing new design circuit level methodology for the implementation of an sCLB. The security level of the sCLB is significantly enhanced by the design of its combinational part (LUT block) based on a dual-rail precharge MUX (DPMUX). The sCLB was implemented in a configurable array and fabricated in 65-nm CMOS technology. Silicon measurements proved the effectiveness of the approach. The security level was evaluated using advanced power analysis techniques. In particular, the number of secret bits that can be learned (mutual information) by a CPA attack dropped from 4 b (out of 4) after 1200 power traces for a conventional LUT design to only 2.56 b after 19.2-M power traces.