Abstract We demonstrate the fabrication and performance evaluation of physical reservoir computing (PRC) using a random network gold-nanoparticles (GNPs). fabricated two arrays GNPs with six electrodes on one sample. Electrical measurements for each array parallelized were conducted at temperatures 4.2 K, 77 294 K. The connections brought varied tunneling resistances, resulting in various output voltages. computational was assessed second-order nonlinear autoregression moving average task....

The propagation of acoustic phonons between mesoscopic superconducting devices on a Si substrate with SiO2 surface layer was studied in terms emission-detection measurements an energy approximately 350μeV. emitter and detector the were composed Al/AlOx/Al junctions, recombination Al electrode used for measurement. It observed that propagated laterally from to as well vertical into interior substrate. results comparative measurement using device etched groove indicate lateral path is almost...

A novel superconducting neuron circuit and two types of variable synapses, which are based on quantum interferometer devices (SQUIDs), presented. with good input-output isolation steep threshold characteristics is accomplished using a combination single-junction SQUID coupled to double-junction SQUID. The state the represents state, output voltage SQUID, operated in nonlatching mode shunt resistors, sigmoid-shaped function input. Both synapse circuits composed multiple shunted SQUIDs. first...

The design and operation of a 9 bit superconductive single‐flux‐quantum (SFQ) digital‐to‐analogue converter (DAC) are presented. DAC comprises variable SFQ pulse number multiplier 100‐fold voltage multiplier. An pulse‐frequency modulation technique is employed for coding the analogue output voltage. fabricated using an Nb Josephson integration technology. Its waveform, amplitude which up to 2.54 m V pp , controlled by digital input signals from room‐temperature data generator.

Abstract Rapid-single-flux-quantum digital-to-analogue converters (RSFQ-DACs) are now under development for ac voltage standard applications. The multiplier (VM), which precisely amplifies the input voltage, is a key component RSFQ-DACs. Because amount of bias current conventional VM increases in proportion to its multiplication factor, we have been looking device operated on different principle. In this paper, report our design 1000-fold comprising double flux quantum amplifiers (DFQAs)...

Synthesis of sinusoidal voltage waveform is a unique application in single-flux-quantum (SFQ) digital electronics. In this paper, the authors present synthesizer based on SFQ pulse-frequency modulation. It comprises variable pulse-number-multiplier (PNM) and code generator (CG) integrated same chip. The output determined by multiplication factor variable-PNM, which controlled from CG instead room-temperature variable-PNM realizes 5-bit resolution with factors between 33 64. generates codes...

We evaluate the input–output characteristics of a 1000-fold voltage multiplier designed for single-flux-quantum (SFQ) digital-to-analog converters. The multiplication is based on double-flux-quantum amplifier (DFQA) that was originally proposed by Herr in 2005. have and fabricated 999-stage DFQA using Nb/AlOx/Nb integration technology. In experiments, we used two methods feeding input SFQ pulse train. one an overbiasing method, i.e., train generated at overbiased junction. A with errors less...

A superconducting neural circuit is fabricated for the first time by use of a niobium integrated-circuit technology. Fluxon pulses on Josephson transmission lines (JTLs) are used as impulses. In this threshold element (a neuron) composed two JTL elements connected through resistor. The conductance value resistor represent synaptic strength. fan-in and fan-out accomplished biased branches. operation 2-bit based A/D converter successfully observed. These circuits do not require any hysteretic...

Abstract A digital-to-analogue converter (DAC) consisting of single-flux-quantum (SFQ) circuitry is known to generate accurate analogue voltages defined by the Josephson relationship. We have been developing SFQ-DACs pulse-frequency modulation (PFM) type. Toward voltage standard applications SFQ-DACs, we set target values for amplitude and resolution at 20 mV pp 10 bits, respectively. So far, reported a 5-bit, 10-μV quasi-sine waveform generator comprising PFM-type SFQ-DAC integrated with an...

The current-voltage characteristics of two long capacitively coupled one-dimensional arrays small Josephson junctions were measured, where the coupling capacitance was comparable with junction. current in both simultaneously measured at various applied magnetic fields voltage to only one arrays. induced unbiased array beyond threshold for Coulomb blockade biased array. direction is same as that other when field and Cooper-pair tunneling dominant, while it changes opposite large...

We present percolative arrays of gold nanoparticles (NPs) formed in a resist groove. To enhance the connection probability, width groove (140 nm) was designed to be approximately five times larger than diameter NPs (30 nm). Two-stage deposition employed form bridge connections between source and drain electrodes. Dithiol molecules coated on surfaces worked as tunnel barriers. 5 12 samples exhibited Coulomb blockade characteristics, one which gate response confirmed.

With a 10 μm×10 μm mesa patterned on Bi2Sr2CaCu2O8 single crystals, we measure the current–voltage (I–V) curves of stack intrinsic Josephson junctions. Current steps are observed at an equal voltage spacing 4 mV when sample is subjected to microwave radiation around 7 GHz. increase power, more occur while between neighboring does not seem change. The magnitude each step depends power in oscillating way. Tuning frequency causes such over separate ranges, and range quite narrow. A temperature...

Mutual inductances between two superconducting strip lines coupled through a grounded shield layer are evaluated by both experiments and numerical calculation. A conventional quantum interference device method on Nb Josephson integrated circuit chip is employed for experiments. Four test circuits designed to investigate the effects of ground contacts. Grounding at one point or points located perpendicular line direction does not improve shielding effect, whereas grounding parallel reduced...

We propose a detailed model of single-electron turnstile device in which each island electrode has finite self-capacitance. The Coulomb blockade (CB) regions are obtained by calculating the free energy system, and graphically presented gate-charge versus bias-voltage plane. confirm CB to be octagonal, instead quadrilateral conventional model.

One of the unique applications single-flux-quantum (SFQ) circuitry is a digital-to-analog converter (DAC) with fundamental accuracy based on Josephson effect. Recently, we have proposed DAC frequency modulation output SFQ pulse train. A variable pulse-number multiplier (PNM) key component for frequency-modulation DAC. In this paper, report our design and test PNM in which multiplication factor determined by sum selected trains coming from series array toggle flip-flops. 64-fold designed...

SFQ digital-to-analog converters (DACs) are one of the candidates for AC voltage standards. We have proposed SFQ-DACs based on frequency modulation (FM). Bipolar output is required applications standards, while our previous generated only positive voltages. In this paper, we present design a 4-bit bipolar triangle waveform generator comprising an SFQ-DAC. The has two ports. Synthesized half-period waveforms alternately in realized by observing differential between confirmed 72-μVPP at 35.7 Hz.

Using c-axis-oriented oxygen-deficient YBa2Cu3O7−δ film deposited across a low-angle step on SrTiO3 substrate, we successfully demonstrated intrinsic Josephson effects. In addition to several voltage jumps of large amplitudes (a few millivolts) and remarkable hysteresis the dc current–voltage curves, observed upturns curves under microwave irradiation which appeared at increasingly high voltages with increasing power. We proposed explain this observation in terms high-order microwave-induced...

We investigated current–voltage characteristics (IVCs) of intrinsic Josephson junctions (IJJs) for c-axis oriented La1.85Sr0.15CuO4 thin films. fabricated IJJs with two kinds structures. One was a mesa structure junction area 22–194 μm2 by using conventional photolithography and Ar-ion milling, the other microbridge 1.1–3.6 focused-ion-beam technique. The mesa-type exhibited resistively-shunted-junction-like IVCs no hysteresis. temperature dependence their critical current followed...

The author numerically demonstrates that a resistive superconducting quantum interference device (RSQUID) with two nonhysteretic Josephson junctions works as relaxation oscillator. Sequential switching of the transfers positive and negative flux quanta in RSQUID loop one by one. Differently from conventional two-junction device, dissipative does not maintain quantized flux, hence, finite can be accumulated during sequential junctions. When reaches critical value, corresponding current...

A hardware random number generator using Josephson oscillation and a few single flux quantum (SFQ) logic gates is presented. The circuit of the consists one toggle flip flop gate. prototype designed by cells based on 2.5-kA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> Nb/AlOx/Nb integration process. fundamental operation at hundred megahertz sampling frequency confirmed numerical simulation when DC/SFQ converter used for generating...

A distinct Bloch nose was demonstrated in the current–voltage characteristics of a one-dimensional array 20 small Josephson junctions. Arrays direct-current superconducting quantum interference device (dc-SQUID) structures were used as leads to junctions, and environmental impedance tuned with magnetic field. The observed had negative differential resistance its magnitude large 14.3 MΩ, blockade voltage 0.36 mV, decrease 0.21 mV due oscillation, all which are larger than those obtained...

We present numerical and experimental investigation on mutual inductance coupled through a superconducting Nb thin film. The extraction program FastHenry with superconductor support is used for calculation. self- inductances of two strip lines are calculated as functions the width shield layer inserted between them. results demonstrate that coupling reduced increasing width. A quantum interference method employed to measure IC chips. agree results.