Gate Operation Research Articles

Pursuing high-fidelity control of spin qubits in natural Si/SiGe quantum dot

Electron spins in silicon quantum dots are a promising platform for fault-tolerant quantum computing. Low-frequency noise, including nuclear spin fluctuations and charge noise, is a primary factor limiting gate fidelities. Suppressing this noise is crucial for high-fidelity qubit operations. Here, we report on a two-qubit quantum device in natural silicon with universal qubit control, designed to investigate the upper limits of gate fidelities in a non-purified Si/SiGe quantum dot device. By employing advanced device structures, qubit manipulation techniques, and optimization methods, we have achieved single-qubit gate fidelities exceeding 99% and a two-qubit controlled-Z (CZ) gate fidelity of 91%. Decoupled CZ gates are used to prepare Bell states with an average fidelity of 91%, typically exceeding previously reported values in natural silicon devices. These results underscore that even natural silicon has the potential to achieve high-fidelity gate operations, particularly with further optimization methods to suppress low-frequency noise.

Analysis and Implementation of Quantum Gates (X, Z, Y, Hadamard CNOT and CCNOT) by using matrices for Quantum Computing

The constraints of present supercomputers in addressing exponentially intricate problems are apparent, as these jobs sometimes necessitate hundreds or even thousands of years due to the exponential increase in computational requirements. Quantum computing, which utilizes concepts from quantum physics and operates with qubits, offers a promising solution by significantly decreasing problem-solving durations to only seconds or minutes. Using IBM's quantum computing platform, this work investigates the construction and analysis of fundamental quantum gates, including X, Z, Y, Hadamard, CNOT, and CCNOT. This work presents a comprehensive analysis of these gates using matrix representations, demonstrating their operational mechanics and algebraic functions, and fundamental role of matrix theory in quantum gate operations and its contribution to the future development of quantum computing.

2D-SnS-Embedded Schottky Device with Neurotransmitter-Like Functionality Produced Using Proximity Vapor Transfer Method for Photonic Neurocomputing.

Neuromorphic computing, which involves the creation of artificial synapses capable of mimicking biological brain activity, has intrigued researchers in the field of artificial intelligence (AI). To advance neuromorphic computing, a highly efficient 2D material-based artificial synapse capable of performing logical and arithmetic operations must be developed. However, fabricating large, uniform films or high-quality structures of 2D materials remains challenging because of their multistep and complex fabrication processes. In the present study, to produce large (Ø ≈ 3 in.), uniform, transparent neuromorphic devices, a novel single-step approach called proximity vapor transfer (PVT) that utilizes van der Waals (vdW) materials is employed. This single-step technique, which involves the fabrication of vdW materials on various substrates (glass, ITO, AZO, Mo, and Cu), allows control of the thickness and bandgap tunability. The Schottky device developed via the PVT method using vdW SnS with neurotransmitter (acetylcholine)-like functionality emulates biological synapses and exhibits photoelectronic synaptic behavior with wide-field-of-view synaptic plasticity. In addition, logic gate operations (NOT, OR, AND), reward-cascade neurotransmission, and imaging can be performed using 3 × 3 arrays of the device. This study represents a significant step toward the development of transparent and large-area synaptic devices, which are crucial for advancing AI applications.

Guidance of fish to the fishway by gate release and confirmation of induction effect

A fishway is a structure that aids fish migration by preventing the blockage of migration paths by dams. However, excessive water through a dam’s gate prevents fish from reaching the fishway. We hypothesized that fishways are sensitive to dams, especially those with independent gates to release water downstream in different spatial patterns. To test this, the sensitivity of fishways to the coordinated operation of multiple gates was investigated via controlled systematic gate manipulation. By manipulating dam gates, we aimed to obtain hydraulic phenomena that circumvent the obstacles to fishways. Numerical model simulations and actual dam discharge experiments showed that releasing water from a gate near fishways facilitated continuity between the downstream regions and fishways, eliminating circulating eddy flows at the fishway entrance. For biovalidation, Oncorhynchus keta was radio-tagged and released ∼1 km downstream of the dam after applying the existing (circulation flow) and new operation methods (no circulation flow). The arrival rate to the fishway was only 40% in the presence and 100% in the absence of circulating flow; this corroborates our hypothesis by showing that changing the dam’s flow release pattern to eliminate circulating flow ensured hydraulic continuity between the mainstream river region and fishways, benefiting fish passage.

Structural Health Monitoring and Failure Analysis of Large-Scale Hydro-Steel Structures, Based on Multi-Sensor Information Fusion

Large-scale hydro-steel structures (LS-HSSs) are vital to hydraulic engineering, supporting critical functions such as water resource management, flood control, power generation, and navigation. However, due to prolonged exposure to severe environmental conditions and complex operational loads, these structures progressively degrade, posing increased risks over time. The absence of effective structural health monitoring (SHM) systems exacerbates these risks, as undetected damage and wear can compromise safety. This paper presents an advanced SHM framework designed to enhance the real-time monitoring and safety evaluation of LS-HSSs. The framework integrates the finite element method (FEM), multi-sensor data fusion, and Internet of Things (IoT) technologies into a closed-loop system for real-time perception, analysis, decision-making, and optimization. The system was deployed and validated at the Luhun Reservoir spillway, where it demonstrated stable and reliable performance for real-time anomaly detection and decision-making. Monitoring results over time were consistent, with stress values remaining below allowable thresholds and meeting safety standards. Specifically, stress monitoring during radial gate operations (with a current water level of 1.4 m) indicated that the dynamic stress values induced by flow vibrations at various points increased by approximately 2 MPa, with no significant impact loads. Moreover, the vibration amplitude during gate operation was below 0.03 mm, confirming the absence of critical structural damage and deformation. These results underscore the SHM system’s capacity to enhance operational safety and maintenance efficiency, highlighting its potential for broader application across water conservancy infrastructure.

Heterocyclic-based Optical Responsive Chemosensors for the detection of Arsenite and Phosphate in semi-aqueous medium: Application in Logic gate operations, RGB tool, and DFT studies

Highly selective and sensitive organic chemosensors S2R1-S2R3 were synthesized using thienyl-substituted pyridine derivative and characterized by various spectroscopic techniques. The effect of substituents on selectivity is observed in the chemosensors S2R1 through S2R3, with the rate of reactivity toward ions following the trend as -NO2 > -CN > -OCH3 group. The chemosensor S2R1 exhibited selectivity towards arsenite and phosphate, achieving a Limit of Detection (LOD) of 0.2672 ppm and 0.5042 ppm, respectively, in 30% aq. (CH3)2SO solution. It was also observed that S2R2 was selective for PO43− ions in 100% (CH3)2SO solution with an LOD of 0.521 ppm. The spectral redshifts observed in the organo-aqueous media potentializes the sensor to be colorimetrically active. The probe S2R1 showed the lowest LOD and high binding constant with AsO2− and PO43− ions. Other characterization techniques, such as electrochemical studies, 1H-NMR titration, UV-visible titration, and DFT experiments, demonstrated the sensing mechanism of arsenite and phosphate ions with the chemosensors through an intermolecular hydrogen bonding and intermolecular charge transfer (ICT) process followed by its practical applicability for real world-sensing.

Modeling Operations in System-Level Real-Time Control for Urban Flooding Reduction and Water Quality Improvement—An Open-Source Benchmarked Case

Advancements in smart sensing and control technologies enable urban drainage engineers to retrofit stormwater storage facilities with real-time control devices for mitigating stormwater in-site overflow, downstream flooding, and overloaded total suspended solids (TSS) in drainage pipes. While the smart technology can improve the performance of the static drainage systems, coordinatively controlling multiple valve and gate operations poses a significant challenge, especially at a large-scale watershed. Using a benchmark stormwater model located at Ann Arbor, Michigan, USA, we assessed the impact of different real-time control strategies (local individual downstream control and system-level multiple control) on balancing flooding mitigation at downstream outlets and TSS reduction at upstream storage units, such as detention ponds. We examined changes in peak water depth, outflow, and TSS as indicators to assess changes in water quantity and quality. The results indicate that system-level control can reduce peak water depth by up to 7.3%, reduce flood duration by up to 34%, and remove up to 67% of total suspended solids compared with a baseline uncontrolled system, with the outflow from upstream detention ponds being the most important hydraulic indicator for control strategy rule set-up. We find that system-level control does not always outperform the individual downstream controls, particularly in alleviating flooding duration at some downstream outlets. With urban growth and a changing climate, this research provides a foundation for quantifying the benefits of real-time control methods as an adaptive stormwater management solution that addresses both water quantity and quality challenges.

Pipelined information flow in molecular mechanical circuits leads to increased error and irreversibility

Pipelining is a design technique for logical circuits that allows for higher throughput than circuits in which multiple computations are fed through the system one after the other. It allows for much faster computation than architectures in which inputs must pass through every layer of the circuit before the next computation can begin (phased chaining). We explore the hypothesis that these advantages may be offset by a higher error rate, logical irreversibility, and greater thermodynamic costs by simulating pipelined molecular mechanical circuits using an explicit physical model. We observe the emergent logical irreversibility, and see that the simultaneous action of multiple components indeed leads to a higher error rate than in phase-chained circuits. The thermodynamic costs of operating the gates are much larger than in equivalent phase-chained circuits, and these costs do not appear to tend to zero in the limit of slowgate operation. Redesigning the gates to eliminate errors and artificially enforcing logical reversibility reduces the thermodynamic costs and recovers thermodynamically reversible behavior in the limit of slow gate operation. The breakdown of logical reversibility and accuracy are both associated with a breakdown of the digital behavior of the device, likely contributing to thermodynamic costs that are large relative to the scale of the information being processed. Published by the American Physical Society 2024

Ultra-Low Power Consumption Artificial Photoelectric Synapses Based on Lewis Acid Doped WSe2 for Neuromorphic Computing.

Capitalizing on the extensive spectral capacity and minimal crosstalk properties inherent in optical signals, photoelectric synapses are poised to assume a pivotal stance in the realm of neuromorphic computation. Herein, a photoelectric synapse based on Lewis acid-doped semiconducting tungsten diselenide (WSe2) is introduced, exhibiting tunable short-term and long-term plasticity. The device consumes a mere 0.1 fJ per synaptic operation, which is lower than the energy required by a single synaptic event observed in the human brain. Furthermore, these devices demonstrate high-pass filtering capabilities, highlighting their potential in image-sharpening applications. In particular, by synergistically modulating the photoconductivity and electrical gate bias, versatile logic capabilities are demonstrated within a single device, enabling it to flexibly perform both Boolean AND and OR gate operations. This work demonstrates a viable approach for Lewis acid-treated TMDs to realize multifunctional photoelectric synapses for neuromorphic computing.

An Experimental Study of Flow and Turbulence Properties near the Rising Sector Gate Mouth Considering the Gate Opening with a PIV Measuring System

Hydraulic structures, such as movable weir gates, are widely installed in rivers and streams for various purposes. Among these is the rising sector gate, which is the focus of this study. This research investigated how different gate openings affect flow velocity and turbulence distributions at the gate mouth. A hydraulic analysis of flow and turbulence characteristics near the mouth of a rising sector gate model was conducted through laboratory experiments with various flow conditions and gate openings utilizing a Particle Image Velocimetry (PIV) system. Experimental tests were carried out with two gate-opening angles (30 and 45 degrees). The PIV measurements revealed significant variations in flow velocity and turbulence properties in response to the gate openings and flow conditions. Notably, in the vicinity of the gate mouth, where the flow regime changes rapidly between the upstream and downstream regions, the turbulence properties in the upstream part of the gate mouth were more than twice those in the downstream part. Additionally, the streamwise distribution of depth-averaged relative turbulence intensity was analyzed. The results showed that the depth-averaged relative turbulence intensity decreased by nearly half as the gate opening increased from 30 to 45 degrees, with the lowest values observed at the gate mouth, followed by an increase downstream. A functional relationship between the maximum flow velocity at the gate mouth during underflow operation and the Froude number was established to guide practical gate operation in the field.

Morphological and geological responses of barrier estuaries to dam-opening systems

River discharge depending on the dam gate operation method is an important factor underlying changes in estuarine sedimentation dynamics, but comprehensive studies are limited by data collection constraints. The hydrological operation of Nakdong Dam, designed to prevent seawater intrusion by opening during ebb tides and heavy rains and closing during flood tides, presents an ideal setting for such investigations. This study focused on the Nakdong River Estuary (NRE), utilizing aerial photography, bathymetry data, and sedimentation rate data to determine alterations in sediment transport and deposition patterns within the two tributary estuaries. Spatial discrepancies in sedimentation patterns across the eastern and western regions of the NRE were particularly evident in the spatial variations of textural characteristics and sedimentation rates. An enhanced ebb tidal prism resulting from dam gate opening in the eastern region caused the development of erosional topography and a rough depositional environment, forming a landward migrating (transgressive) barrier island system. Conversely, the predominantly closed dam gates in the western region maintained a consistent deposition pattern due to a regular tidal prism, facilitating the formation of sedimentary topography and fine sediment deposition. Consequently, barrier islands followed a seaward building (prograding) system. Therefore, the results suggested a role of modern dam gate operation as a major sedimentation mechanism, providing valuable insights for the sustainable management of estuarine sediment environments.

Research on the influence of rigid body modes on the operating vibration of arc gate

Abstract The 5# arc working gate of Jiangshan Wanyao Reservoir is composed of the suspension system of the gate and the steel wire rope, which has a serious vibration phenomenon when running without water. Firstly, the rigid body modal analysis of the gate suspension system is analyzed, the position size of key components such as gate support hinge shaft, gate motion guide embedded parts, and main beam position state is measured and evaluated on site, and the dynamic stress and vibration of the support arm are tested and analyzed during gate operation. It is concluded that the influence rule and weight of the steel wire rope on the rigid body mode of the gate, the torsional position of the gate, and the uneven operation condition of the side guide lead to the rigid body mode of the gate. It is suggested to improve the twisting state of the gate, adjust the unevenness of the embedded parts, and weaken the factors that induce the modal vibration of the rigid body.

Scheme of preparing cluster states with cat qubits

Abstract Cluster states are essential quantum resources for one-way quantum computations and quantum networks. The reliable generation of cluster states in specific quantum systems is crucial for initializing complex quantum operations. In this paper, we introduce an efficient scheme for the deterministic preparation of a cluster state via circuit quantum electrodynamics (QED). Our scheme involves four individual microwave resonators, each of which is coupled to a superconducting transmon qutrit. We demonstrated that a four-cqubit cluster state can be achieved using three controlled-phase gate operations. The cluster state is prepared deterministically, eliminating the need for measurement-based feedback. Throughout these operations, the qutrit remains in its ground state, effectively minimizing decoherence from the qutrit. Numerical simulations suggest that our scheme can generate high-fidelity cluster states using current-circuit QED technology. We believe that our model will facilitate exploration of future large-scale continuous-variable quantum information processing systems.

Design and Optimization of Water Level Control Gate System in Malwathu Oya River, Sri Lanka

This research focuses on improving flood management of the Malwathu Oya River in Anuradhapura Historical City, Sri Lanka, by designing an efficient gate system for the weir of Halpan Ela in the Malwathu Oya River. Frequent flooding threatens agriculture, infrastructure, and public safety in this region. This research aims to enhance water level control in the upper reach of Halpan Ela Anicut by evaluating rainfall patterns, tank spillway efficiency, and gate operation challenges. Historical data on rainfall and tank spillage were analyzed. Flow simulations revealed significant pressure differences, with the existing gate structure showing an upstream pressure of 114,492.5 Pa at a maximum flow of 1740 m3/s, compared to 105,406 Pa for the new flap gate system at the same flow rate. This represents a pressure difference of 9 kPa, equivalent to a 0.9 m water head. Despite the system’s estimated cost of USD 0.1 million, the potential reduction in river flood damage, which currently exceeds USD 0.2 million annually, demonstrates its value. This research emphasizes the effectiveness of the flap gate system in reducing flood risks in Anuradhapura City compared to the existing gate type, though it is only a part of a broader flood mitigation strategy.

Influence of Check Gate Construction on Operation of Check Gate in Ship Lock

Influence of Check Gate Construction on Operation of Check Gate in Ship Lock

Boolean Logic Gate Operation in Bacteriorhodopsin of Purple Membrane Based on a Molten Globule-like State.

Bacteriorhodopsin (bR) of purple membrane (PM) has increasing technical interests, particularly in photonic devices and bioelectronics. The present work has concerned with monitoring the temperature dependence of passive electric responses in-plane and out-of-plane of the membranes. Based on thermal properties observed orthogonally here for PM, a high-temperature intermediate of bR has been suggested to populate at around 60 °C, which may be ascribed to a molten globule-like state. This intermediate has been found to be enclosed between two reversible thermal transitions for PM. Large-scale turnover in the energy of activation, for these two thermal transitions, occurs steeply at such state at 60 °C, above which does bR reverse the sign of dielectric anisotropy (i.e. crossover) provided the operating frequency should be above the crossover frequency, at which the reversal occurs. No such crossover was found to occur below the crossover frequency, even above the crossover temperature (i.e. 60 °C). Likewise, no such crossover was found to occur below the crossover temperature, even above the crossover frequency. Relying on this reasoning, a logic gate operation may be declared implicating bR for bioelectronics and sense technological relevance. In addition, the results specify "dual frequency" as well as "dual temperature" characteristics to bacteriorhodopsin.

Does the upstream gate control scheme threaten the safety of extra-long pressurized water diversion tunnel: Gas–liquid evolution characteristics of the filling process

With the promotion of China's “National Water Networks” strategy, extra-long pressurized water diversion tunnels are increasingly implemented in trans-regional and trans-basin water diversion projects. Existing projects commonly employ middle or downstream gate control schemes, but setting the control gate at the upstream offers a new approach to mitigate the adverse effects of flow pattern changes and hydraulic inertia caused by gate operations. However, there is no precedent for a 200 km-extra-long pressurized water diversion tunnel worldwide, it is not clear whether deviating from established norms will create new problems, and how to illustrate the hydraulic evolution characteristics under this scheme is the primary challenge. Therefore, this study takes a follow-up project for China's South-to-North Water Diversion Project as the research object: (1) Modeling: establish a mathematical model of an extra-long pressurized water diversion tunnel based on the movement of gas–liquid interface; and (2) Simulating: analyze the transient process of two arrangement schemes (single-slope and variable-slope) under various operating conditions. The study reveals the characteristics of pressure distribution, flow rates, and water level variations along the tunnel, conducting a comparative analysis of different arrangement schemes. The findings demonstrate that, even under the most unfavorable assumption, the key indicators during the water filling process remain within the acceptable range specified by engineering design. Therefore, the adoption of the upstream gate control scheme for the extra-long water diversion tunnel is considered feasible. This research provides specific theoretical basis and technical support for the construction and operation of water diversion projects.

Direct observation of a few-photon phase shift induced by a single quantum emitter in a waveguide

Realizing a sensitive photon-number-dependent phase shift on a light beam is required both in classical and quantum photonics. It may lead to new applications for classical and quantum photonics machine learning or pave the way for realizing photon-photon gate operations. Nonlinear phase-shifts require efficient light-matter interaction, and recently quantum dots coupled to nanophotonic devices have enabled near-deterministic single-photon coupling. We experimentally realize an optical phase shift of 0.19π ± 0.03 radians ( ≈ 34 degrees) using a weak coherent state interacting with a single quantum dot in a planar nanophotonic waveguide. The phase shift is probed by interferometric measurements of the light scattered from the quantum dot in the waveguide. The process is nonlinear in power, the saturation at the single-photon level and compatible with scalable photonic integrated circuitry. The work may open new prospects for realizing high-efficiency optical switching or be applied for proof-of-concept quantum machine learning or quantum simulation demonstrations.

Gate operations for superconducting qubits and non-Markovianity

While the accuracy of qubit operations has been greatly improved in the last decade, further development is demanded to achieve the ultimate goal: a fault-tolerant quantum computer that can solve real-world problems more efficiently than classical computers. With growing fidelities even subtle effects of environmental noise such as qubit–reservoir correlations and non-Markovian dynamics turn into the focus for both circuit design and control. To guide progress, we disclose, in a numerically rigorous manner, a comprehensive picture of the single-qubit dynamics in presence of a broad class of noise sources and for entire sequences of gate operations. Thermal reservoirs ranging from Ohmic to deep 1/fɛ-like sub-Ohmic behavior are considered to imitate realistic scenarios for superconducting qubits. Apart from dynamical features, fidelities of the qubit performance over entire sequences are analyzed as a figure of merit. The relevance of retarded feedback and long-range qubit–reservoir correlations is demonstrated on a quantitative level, thus, providing a deeper understanding of the limitations of performances for current devices and guiding the design of future ones. Published by the American Physical Society 2024

Real-time regulation of detention ponds via feedback control: Balancing flood mitigation and water quality

Detention ponds can mitigate flooding and improve water quality by allowing the settlement of pollutants. Typically, they are operated with fully open orifices and weirs (i.e., passive control). Active controls can improve the performance of these systems: orifices can be retrofitted with controlled valves, and spillways can have controllable gates. The real-time optimal operation of its hydraulic devices can be achieved with techniques such as Model Predictive Control (MPC). A distributed quasi-2D hydrologic-hydrodynamic coupled with a reservoir flood routing model is developed and integrated with an MPC algorithm to estimate the operation of valves and movable gates in real-time. The control optimization problem is adapted to switch from a flood-related algorithm focusing on mitigating floods to a heuristic objective function that aims to increase the detention time when no inflow hydrographs are predicted. The case studies show the potential results of applying the methods developed in a catchment in Sao Paulo, Brazil. The performance of MPC compared to alternatives that do not change the operation over time with either fully or partially open valves and gates are tested. Comparisons with HEC-RAS 2D indicate volume and peak flow errors of approximately 1.4% and 0.91% for the watershed module. Simulating two consecutive 10-year storms shows that the MPC strategy can achieve peak flow reductions of 79%. In contrast, the passive scenario has nearly half of the performance (41%). A 1-year continuous simulation results show that the passive scenario with 25% of the valves opened can treat 12% more runoff compared to the developed MPC approach, with an average detention time of approximately 6 h. For the MPC approach, the average detention time is nearly 14 h, indicating that both control techniques can treat similar volumes; however, the proxy water quality for the MPC approach is enhanced due to the longer detention times achieved.