Parallel Gate Research Articles

Impact of Parallel Gating on Gate Fidelities in Linear, Square, and Star Arrays of Noisy Flip‐Flop Qubits

AbstractSuccessfully implementing a quantum algorithm involves maintaining a low logical error rate by ensuring the validity of the quantum fault‐tolerance theorem. The required number of physical qubits arranged in an array depends on the chosen Quantum Error Correction code and the achievable physical qubit error rate. As the qubit count in the array increases, parallel gating —simultaneously manipulating many qubits— becomes a crucial ingredient for successful computation. In this study, small arrays of a type of donor‐ and quantum dot‐based qubits, known as flip‐flop (FF) qubits, are investigated. Simulation results of gate fidelities in linear, square and star arrays of four FF qubits affected by realistic 1/f noise are presented to study the effect of parallel gating. The impact of two, three and four parallel one‐qubit gates, as well as two parallel two‐qubit gates, on fidelity is calculated by comparing different array geometries. The findings can contribute to the optimized manipulation of small FF qubit arrays and the design of larger ones.

Fast, universal scheme for calibrating microwave crosstalk in superconducting circuits

A challenge in building large-scale superconducting quantum processors is the precise control and manipulation of the qubit state. However, the crosstalk between the microwave control lines impedes the parallel execution of high-fidelity digital and analog quantum operations. Here, we propose and demonstrate a universal compensation protocol for calibrating the microwave signal crosstalk. We also introduce amplified error sequences to optimize accuracy. Furthermore, we show a definitive improvement in parallel gate operations with crosstalk cancellation, demonstrating the technique's effectiveness. This work paves the way for superconducting hardware that features the automated calibration of microwave crosstalk, leading to enhanced fidelities in multiqubit circuits.

Parallel Gate Fidelity of Flip‐Flop Qubits in Small 1D‐ and 2D‐Arrays in a Noisy Environment

AbstractThe long coherence time of donor atom nuclear spin states and of its bounded electron in can be exploited to define a qubit. This work is focused on a type of donor‐ and quantum dot‐based qubit, the flip‐flop (FF) qubit, that leverages antiparallel electron‐nuclear spin states of a donor atom controlled by an electric field. It can provide long‐range inter‐qubit interactions in the order of some hundreds of nanometers, thus relaxing the common constraints and tolerances on inter‐qubit distances in donor‐based qubits. Simulation results of linear array (LA) and square array (SA) of four FF qubits are presented to study the effect of noise, idle qubits, and simultaneous gating (parallel gating) on gate fidelity. The impact of noise and qubit mutual coupling for both considered types of array are presented and the obtained fidelity results are compared.

Surface trap with adjustable ion couplings for scalable and parallel gates

Surface trap with adjustable ion couplings for scalable and parallel gates

A 43.5dB Gain Unipolar a-IGZO TFT Amplifier with Parallel Bootstrap Capacitor for Bio-signals Sensing Applications.

In this paper, a high gain amplifier with phase compensation loop is presented. A structure of parallel gate cross-coupled transistors to both ends of differential pair drain and source is designed to improves the load impedance, which obtains sufficient gain and further reduces power consumption. A novel capacitor bootstrap load circuit is proposed. The capacitor bootstrap topology is constructed by the drain source resistance of the transistor working in the cut-off region, where the gate source parasitic capacitor of the transistor is in parallel with the bootstrap capacitor rather than the existing series structure, thereby only a small bootstrap capacitor is required. By avoiding the use of large capacitors, chip area can be effectively reduced without compromising performance such as gain and bandwidth. The amplifier is fabricated using 10-μm n-type a-IGZO TFT technology. Measurement results show that the proposed amplifier achieves a voltage gain of 43.5dB and a common mode rejection ratio of 61.2dB while maintaining low power consumption. The amplifier also exhibits a -3dB bandwidth covering 0.4~2.1KHz, encompassing major bioelectric frequency bands. A real-time ECG signal was successfully captured using the fabricated TFT amplifier and gel electrodes. It has great potential in flexible sensing and acquisition applications such as electro cardiogram (ECG), electro encephalogram (EEG), pulse detection, and other wearable applications.

Concentration gradients probed in microfluidics by gate-array electrolyte organic transistor

We propose a device architecture termed gate-array electrolyte gated organic transistor (GA-EGOFET) that quantitatively measures the solute concentration gradient created in a spatially inhomogeneous solution, for instance a (biological) fluid. The integrated H-cell microfluidics yields a diffusive concentration profile along the microfluidics channel according to the flow rate of the input streams. We demonstrate this concept by monitoring the formation of self-assembly monolayers (SAMs) on top of an array of parallel Au gate electrodes exposed to a different local concentration of alkanethiols. The deposition rate and the coverage both increase from the entrance towards the H-cell end. The voltage change at each gate is transduced in the transfer curve acquired with the specific gate electrode. For short chain length SAMs (n = 3), the trend of the current hints to a diffusion-limited surface reaction. For longer thiols (n = 6, 9), instead, the slower surface diffusion or incorporation in the more stable and compact SAM yields a current that is independent of the longitudinal gradient. The microfluidics/GA-EGOFET platform is viable for constructing dose curves in reproducible manner and for validating different electrode functionalization strategies where the deposition rates are different at each substrate site.

Reliability analysis of turbine unit using Intuitionistic Fuzzy Lambda-Tau approach

The current work presents a two phase Intuitionistic Fuzzy (IF) based framework, for investigating the reliability analysis of a Turbine Unit (TU) in a sugar mill process industry. Intuitionistic Fuzzy Lambda Tau (IFLT) approach-based series-parallel expressions have been applied for computing various reliability indices. For series arrangement OR gate transitions expression has been used, and for parallel arrangement AND gate expressions has been used for calculation of reliability parameters for membership and non- membership function. For membership function, system’s availability decreases by 0.000002% for spread value ±15% to±30%, further decreases by 0.000005% for spread value ± 30% to±45%. While, non- membership function-based system’s availability decreases by 0.000003% for spread value ± 15% to±30% and further decreases by 0.000007 % for spread value ± 30% to±45%. The reliability trends at various spreads lay the foundation of studying the failure behaviour of the TU and to plan a maintenance schedule.

Pairwise‐Parallel Entangling Gates on Orthogonal Modes in a Trapped‐Ion Chain

AbstractParallel operations are important for both near‐term quantum computers and larger‐scale fault‐tolerant machines because they reduce execution time and qubit idling. This study proposes and implements a pairwise‐parallel gate scheme on a trapped‐ion quantum computer. The gates are driven simultaneously on different sets of orthogonal motional modes of a trapped‐ion chain. This work demonstrates the utility of this scheme by creating a Greenberger‐Horne‐Zeilinger (GHZ) state in one step using parallel gates with one overlapping qubit. It also shows its advantage for circuits by implementing a digital quantum simulation of the dynamics of an interacting spin system, the transverse‐field Ising model. This method effectively extends the available gate depth by up to two times with no overhead when no overlapping qubit is involved, apart from additional initial cooling. This scheme can be easily applied to different trapped‐ion qubits and gate schemes, broadly enhancing the capabilities of trapped‐ion quantum computers.

Recognize enhanced temporal-spatial-spectral features with a parallel multi-branch CNN and GRU.

Deep learning has been applied to the recognition of motor imagery electroencephalograms (MI-EEG) in brain-computer interface, and the performance results depend on data representation as well as neural network structure. Especially, MI-EEG is so complex with the characteristics of non-stationarity, specific rhythms, and uneven distribution; however, its multidimensional feature information is difficult to be fused and enhanced simultaneously in the existing recognition methods. In this paper, a novel channel importance (NCI) based on time-frequency analysis is proposed to develop an image sequence generation method (NCI-ISG) for enhancing the integrity of data representation and highlighting the contribution inequalities of different channels as well. Each electrode of MI-EEG is converted to a time-frequency spectrum by utilizing short-time Fourier transform; the corresponding part to 8-30Hz is combined with random forest algorithm for computing NCI; and it is further divided into three sub-images covered by α (8-13Hz), β1 (13-21Hz), and β2 (21-30Hz) bands; their spectral powers are further weighted by NCI and interpolated to 2-dimensional electrode coordinates, producing three main sub-band image sequences. Then, a parallel multi-branch convolutional neural network and gate recurrent unit (PMBCG) is designed to successively extract and identify the spatial-spectral and temporal features from the image sequences. Two public four-class MI-EEG datasets are adopted; the proposed classification method respectively achieves the average accuracies of 98.26% and 80.62% by 10-fold cross-validation experiment; and its statistical performance is also evaluated by multi-indexes, such as Kappa value, confusion matrix, and ROC curve. Extensive experiment results show that NCI-ISG + PMBCG can yield great performance on MI-EEG classification compared to state-of-the-art methods. The proposed NCI-ISG can enhance the feature representation of time-frequency-space domains and match well with PMBCG, which improves the recognition accuracies of MI tasks and demonstrates the preferable reliability and distinguishable ability. This paper proposes a novel channel importance (NCI) based ontime-frequencyanalysis to develop an image sequences generation method (NCI-ISG) for enhancing the integrity of data representation and highlighting the contribution inequalities of different channels as well. Then, a parallel multi-branch convolutional neural network and gate recurrent unit (PMBCG) is designed to successively extract and identify the spatial-spectral and temporal features from the image sequences.

Single-electron pump in a quantum dot array for silicon quantum computers

It is necessary to load single electrons into individual quantum dots (QDs) in an array for implementing fully scalable silicon-based quantum computers. However, this single-electron loading would be impacted by the variability of the QD characteristics, and suppressing this variability is highly challenging even in the state-of-the-art silicon front-end process. Here, we used a single-electron pump (SEP) for loading single electrons into a QD array as a preparatory step to use electrons as spin qubits. We used parallel gates in the QD array as a SEP and demonstrated 100 MHz operation with an accuracy of 99% at 4 K. By controlling the timing of a subsequent gate synchronously as a shutter, we found that the jitter representing electron transfer was less than 10 ns, which would be acceptable for a typical operating speed of around 1 MHz for silicon qubits.

An Optimized Vertical GaN Parallel Split Gate Trench MOSFET Device Structure for Improved Switching Performance

This work proposes a vertical gallium nitride (GaN) parallel split gate trench MOSFET (PSGT-MOSFET) device architecture suitable for power conversion applications. Wherein two parallel gates, and a field plate are introduced vertically on the sidewalls and connected, respectively, to the gate and source. Technology computer-aided design (TCAD) simulator was used in the design process to achieve a specific on-resistance as low as 0.79 mΩ.cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> for the device, which has the capacity of blocking voltages up to 600 V. The peak electric field of the PSGT-MOSFET could well be lowered to 2.95 MV/cm, which is about 17% lower than that of a conventional trench gate MOSFET (TG-MOSFET) near the trench corner with help of suitable design and optimization of trench depth, drift doping, and field plate thickness. The TCAD simulation shows that the higher drift doping on the device performance of PSGT-MOSFET produces ~2× lower switching losses when compared with a similarly rated conventional TG-MOSFET device.

Generation of Greenberger-Horne-Zeilinger States on Two-Dimensional Superconducting-Qubit Lattices via Parallel Multiqubit-Gate Operations

A recent major technological breakthrough in superconducting circuits is the realization of more than 50 qubits arranged on two-dimensional (2D) lattices with tunable nearest-neighbor couplings. We propose a protocol to generate Greenberger-Horne-Zeilinger (GHZ) states on 2D superconducting-qubit lattices by applying multiqubit controlled-$i$swap gates in parallel. The multiqubit gate can be naturally implemented based on an effective three-body interaction, which can be synthesized with appropriate detunings and coupling strengths between qubits. We simulate the preparation process of GHZ states with realistic parameters, and show a $37$-qubit GHZ state can be generated with a controlled-$i$swap depth of $3$. Our proposal provides a more promising method of generating GHZ states on the latest 2D superconducting-qubit architectures and will stimulate the preparation of multiqubit entangled states based on multiqubit gates.

Compact Real-Time Control System for Autonomous Vehicle

Due to global warming, there is an increase in the number of natural disasters occurring around the world. With more disasters happening, post disaster search and rescue personnel are putting their life on the line more often in scouting out the post disaster site and sending in first aid supplies while waiting for rescue vehicles like fire trucks and ambulance to arrive. In Malaysia alone, the use of compact Autonomous Landed Vehicle (ALV) for this purpose is limited. There are many compact ALV that are being developed with microcontrollers and microprocessors such as Arduino and Raspberry Pi as the central control system, but they are fragile and can be damaged easily when used in harsh environments. In addition, multiple microcontrollers and microprocessors are needed for the ALV as parallel processing and limited gates are some of the common problems with microprocessors and microcontrollers. In this paper, a central control system using an FPGA is proposed together with the design of a prototype for the ALV. The ALV consists of three systems: Propulsion System, Sensor System, and Remote-Control System. These systems are integrated together with the Altera DE-115 board as the central control unit of the ALV. Verilog Hardware Description language (Verilog HDL) is used for designing the control system for the ALV. The proposed system is stable, low cost, allows parallel processing and the compact size of the ALV allows smooth manoeuvring through small areas of post disaster sites to scout out the area and send in first aid supplies to the victims.

Design Methodologies for Integrated Quantum Frequency Processors

Frequency-encoded quantum information offers intriguing opportunities for quantum communications and networking, with the quantum frequency processor paradigm—based on electro-optic phase modulators and Fourier-transform pulse shapers—providing a path for scalable construction of quantum gates. Yet all experimental demonstrations to date have relied on discrete fiber-optic components that occupy significant physical space and impart appreciable loss. In this article, we introduce a model for the design of quantum frequency processors comprising microring resonator-based pulse shapers and integrated phase modulators. We estimate the performance of single and parallel frequency-bin Hadamard gates, finding high fidelity values that extend to frequency bins with relatively wide bandwidths. By incorporating multi-order filter designs as well, we explore the limits of tight frequency spacings, a regime extremely difficult to obtain in bulk optics. Overall, our model is general, simple to use, and extendable to other material platforms, providing a much-needed design tool for future frequency processors in integrated photonics.

Crosstalk analysis for simultaneously driven two-qubit gates in spin qubit arrays

One of the challenges when scaling up semiconductor-based quantum processors consists in the presence of crosstalk errors caused by control operations on neighboring qubits. In previous work, crosstalk in spin qubit arrays has been investigated for non-driven single qubits near individually driven quantum gates and for two simultaneously driven single-qubit gates. Nevertheless, simultaneous gates are not restricted to single-qubit operations but also include frequently used two-qubit gates such as the CNOT gate. We analyse the impact of crosstalk drives on qubit operations, such as the CNOT and CPHASE gates. We investigate the case of parallel $Y$ and CNOT gates, and we also consider a two-dimensional arrangement of two parallel CNOT gates and find unavoidable crosstalk. To minimize crosstalk errors, we develop appropriate control protocols.

Parallel Gate Operations Fidelity in a Linear Array of Flip‐Flop Qubits

AbstractQuantum computers based on silicon are promising candidates for long term universal quantum computation due to the long coherence times of electron and nuclear spin states. Furthermore, the continuous progress of micro‐ and nano‐electronics, also related to the scaling of metal–oxide–semiconductor systems, makes it possible to control the displacement of single dopants thus suggesting their exploitation as qubit holders. Flip‐flop qubit is a donor based qubit where interactions between qubits are achievable for distance up to several hundred nanometers. In this work, a linear array of flip‐flop qubits is considered and the unwanted mutual qubit interactions due to the simultaneous application of two one‐qubit and two two‐qubit gates are included in the quantum gate simulations. In particular, by studying the parallel execution of couples of one‐qubit gates, namely and , and of couples of two‐qubit gate, that is, , a safe inter‐qubit distance is found where unwanted qubit interactions are negligible thus leading to parallel gates fidelity up to 99.9%.

Evaluation of the wear and corrosion resistance of coated parallel gate valve

This paper aims to experimentally evaluate the wear and corrosion resistance of the coated active parts surfaces of a cut off valve. This paper presents the electrochemical corrosion, hardness and wear tests of the gate valve coated surfaces with a plastic material, in order to evaluate the seat and gate valve couple behaviour in an aggressive medium containing crude oil with sand particles. Uncoated and coated surfaces were compared and evaluated by the coefficient of friction, wear rates and corrosion resistance. A comparison process between the previous results of the CFD analysis for erosion wear and the test results, at the covered gate valve, is also presented. Keywords: gate valve, solid lubricant, coefficient of friction, corrosion resistance, wear resistance.

Thermophysical impact on the squeezing motion of non-Newtonian fluid with quadratic convection, velocity slip, and convective surface conditions between parallel disks

The present paper considers suction/injection, constant and variable thermophysical influence in squeezing flow of magnetized blood rheological (Casson) fluid model between two parallel disks subjected to nonlinear convection process, slip and convective surface conditions. The unsteady, squeezing, magnetized, and chemically reacting dissipative fluid flowing between parallel disks is modeled and non-dimensionalized via an applicable similarity transformation. An approximate solution of the flow distributions is sought by employing the Chebyshev Collocation Approach (CCA). In the limiting scenario, an excellent agreement in the present results with the existing literature is obtained. The analysis reveals the dominance of constant thermophysical effect over the variable thermo-properties on velocities and temperature field. Higher thermal/solutal Biot number highlighted the dominance of positive squeezing number while its minimal values showcase the dominance of negative squeezing number on flow and energy field. Therein, the squeezing effect remains invariant for some range values of thermal/solutal Biot number, while a rise in velocity slip and suction parameter enhanced the fluid velocities and concentration profiles respectively. Moreover, the current analysis is applicable in moving engines such as in parallel disk gate valve, locomotion of piston in ring where oil is viewed as Casson fluid, thermoforming, injection molding, biomedical use among others.

Modeling the working media flow in shut-off valves with displacement of the regulating body perpendicular to the flow axis

The mathematical model of the working fluid movement in the flow section of the wedge type two-disc parallel gate valve is developed. The simulation of the fluid flow through the valve cavity is carried out, as a result the flow parameters are obtained in a wide range of Reynolds numbers at the entrance to the calculated area. The dependence of the hydraulic resistance as a function of the Reynolds number for liquid and gas flow is calculated. The various positions of the shut-off body in the flow part of the valve are considered and the area of reduced pressures in which the effect of cavitation may occur during fluid flow is estimated.

Comments on “Study and application of discharge calibration for submerged radial gates” by Guo X., Guo Y., Wang T., Fu H., Li J. Flow Meas. Instrum. 78 (2021) 101912, https://doi.org/10.1016/j.flowmeasinst.2021.101912

This paper discusses the capability of Guo et al.'s (2021) equations to determine the discharge of radial gates under submerged flow conditions. It was concluded that Guo et al.'s (2021) equations are associated with error reduction compared to the Incomplete Self-Similarity (ISS) theory and the calibration method. However, it does not have a significant advantage over Energy-Momentum (E-M) approach. Employing E-M principles, new equations were proposed to determine the discharge of radial gates, which has some advantages compared to Guo et al. (2021), such as (1) error reduction under partially and fully submerged flow conditions, (2) least dependence on the empirical constants, (3) uniformity of form over the entire submerged condition, and (4) no need to classify the submerged flow. Field calibration showed that the proposed equations in the present study for a single gate predict the discharge of parallel radial gates with a mean absolute error of less than 4.5% subject to the submerged operation of all open gates.