Performing Logical Operations with Stimuli-Responsive Building Blocks.

Seven all-optical logic gates based on hybrid plasmonic squared-shaped nanoring resonators and strips are proposed, designed, and numerically analyzed using finite element method with COMSOL software package version 5.5. Constructive and destructive interferences between the input port(s) and the control port(s) are the main operating principles used to produce the proposed gates. The ratio of output optical power to the input power at a single port which is called the transmission threshold is selected to be 30% and the resonance wavelength is 1310 nm. All the hybrid plasmonic logic gates are performed in a single structure of 400 nm × 400 nm dimensions and the performance is measured according to the values of transmission at the output port versus a wavelength range from 800 to 2000 nm, contrast ratio, modulation depth, and insertion loss. The transmission exceeds 100% in five gates, 146% at NOT and NAND gates, 202.3% at OR, AND, and XNOR gates. The modulation depth scores are 99.75% at the XNOR gate, 98.5% at the NOR gate, 97.67% at OR, AND, NOT, and NAND gates, and 95.29% for the XOR gate.

Faces that move contain rich information about facial form, such as facial features and their configuration, alongside the motion of those features. During social interactions, humans constantly decode and integrate these cues. To fully understand human face perception, it is important to investigate what information dynamic faces convey and how the human visual system extracts and processes information from this visual input. However, partly due to the difficulty of designing well-controlled dynamic face stimuli, many face perception studies still rely on static faces as stimuli. Here, we focus on evidence demonstrating the usefulness of dynamic faces as stimuli, and evaluate different types of dynamic face stimuli to study face perception. Studies based on dynamic face stimuli revealed a high sensitivity of the human visual system to natural facial motion and consistently reported dynamic advantages when static face information is insufficient for the task. These findings support the hypothesis that the human perceptual system integrates sensory cues for robust perception. In the present paper, we review the different types of dynamic face stimuli used in these studies, and assess their usefulness for several research questions. Natural videos of faces are ecological stimuli but provide limited control of facial form and motion. Point-light faces allow for good control of facial motion but are highly unnatural. Image-based morphing is a way to achieve control over facial motion while preserving the natural facial form. Synthetic facial animations allow separation of facial form and motion to study aspects such as identity-from-motion. While synthetic faces are less natural than videos of faces, recent advances in photo-realistic rendering may close this gap and provide naturalistic stimuli with full control over facial motion. We believe that many open questions, such as what dynamic advantages exist beyond emotion and identity recognition and which dynamic aspects drive these advantages, can be addressed adequately with different types of stimuli and will improve our understanding of face perception in more ecological settings.

The recent progress in quantum computing and space exploration led to a surge in interest in cryogenic electronics. Superconducting devices such as Josephson junction, Josephson field effect transistor, cryotron, and superconducting quantum interference device (SQUID) are traditionally used to build cryogenic logic gates. However, due to the superconducting nature, gate-voltage-based control of these devices is extremely difficult. Even more challenging is to cascade the logic gates because most of these devices require current bias for their operation. Therefore, these devices are not as convenient as the semiconducting transistors to design logic gates. Here, to overcome these challenges, we propose a ferroelectric SQUID (FeSQUID) based voltage-controlled logic gates. FeSQUID exhibits two different critical current levels for two different voltage-switchable polarization states of the ferroelectric. We utilize the polarization-dependent (hence, voltage-controllable) superconducting to resistive switching of FeSQUID to design Boolean logic gates such as Copy, NOT, AND, and OR gates. The operations of these gates are verified using a Verilog-A-based compact model of FeSQUID. Finally, to demonstrate the fanning out capability of FeSQUID-based logic family, we simulate a two-input XOR gate using FeSQUID-based NOT, AND, and OR gates. Together with the ongoing progress on FeSQUID-based non-volatile memory, our designed FeSQUID-based logic family will enable all FeSQUID-based cryogenic computer, ensuring minimum mismatch between logic and memory blocks in terms of speed, power consumption, and fabrication process.

Optical logic gates are important elements in optical computing and optical circuits. In this study, all-optical logic gates, including OR, XOR, XNOR, NAND, and NOT gates, are obtained in a composite structure composed of gyroelectric material and metal based on the interference and absorption of surface waves. In the composite structure, a Y-shaped channel through which surface plasmon polaritons propagate unidirectionally is formed. Through the ingenious one-way surface plasmon polaritons, backscattering and side-scattering generated by the composite structure and influencing the surrounding devices are prohibited effectively. The precisely controlled optical phase difference ensures the realization of five different logic gates with high contrast ratios. The maximum contrast ratios for XOR, XNOR, NAND, and NOT gates are 31.64dB, 43.47dB, 31.47dB, and 43.47dB, respectively. The output logic states "1"or "0" obtained by different logic inputs have nearly the same light intensity. Our research results provide the possibility for constructing all-optical integrated logic devices.

Background and Objectives: Recently, photonic crystals have been considered as the basic structures for the realization of various optical devices for high speed optical communication.Methods: In this research, two dimensional photonic crystals are used for designing all optical logic gates. A photonic crystal structure with a triangular lattice is proposed for making NAND, XNOR, and OR optical logic gates. Using the structure as the intended logic gate is possible without the need to change the structure through the use of the phase difference at the inputs. Line and point defects have been used to propagate light from inputs to output. The logical values "0" and "1", are defined based on the amount of transferred optical power to the output.Results: The simple structure and the use of line and point defects, instead of ring resonators, reduce the complexity of the design and its use in optical logic integrated circuits. Another advantage of proposed structure, in comparison to the previous structures is the reduction in delay time that increases its speed. The maximum delay time of the proposed optical NAND, XNOR, and OR gates is about 0.1ps.Conclusion: In this study, one structure is suggested for realizing NAND, XNOR, and OR logic gates. This structure has a small size and low delay time, and is suitable for use in optical integrated circuits.

All-optical NOR and NOT logic gates based on ring resonator-based plasmonic nanostructures

3 - Synthesizable Code for Basic Logic Components

Antiferromagnets are promising materials for future spintronic applications due to their unique properties including zero stray fields, robustness vs external magnetic fields, and ultrafast dynamics, which have attracted extensive interest in recent years. In this work, we investigate the dynamics of isolated skyrmions in an antiferromagnetic nanotrack with a voltage-gated region. It is found that the skyrmion can be jointly controlled by the driving current and the voltage-controlled magnetic anisotropy gradient. We further propose a design of logic computing gates based on the manipulation of antiferromagnetic skyrmions, which is numerically realized combining several interactions and phenomena, including the spin Hall effect, voltage-controlled magnetic anisotropy effect, skyrmion–skyrmion interaction, and skyrmion–edge interaction. The proposed logic gates can perform the basic Boolean operations of the logic AND, OR, NOT, NAND, and NOR gates. Our results may have a great impact on fundamental physics and be useful for designing future nonvolatile logic computing devices with ultra-low energy consumption and ultra-high storage density.

The capture of phosphoproteins by 14-3-3 proteins mediates actions of insulin

We report a novel nanodevice using π-conjugated polymers and inorganic semiconductor dual composite P–N junctions single nanowire constructed by PEDOT–PbS–PPY (EPP) nanowire as a two-input OR gate. The nanodevices logic gate may show some key value in nanoelectronic components. A team led by Yuliang Li from Beijing, China, has assembled three different semiconductors into a single nanowire that comprises two p-n heterojunctions and acts as an electronic logic gate. Such heterojunctions — the interfaces between p- and n-type semiconductors — are crucial components of a variety of electronic devices. The researchers constructed the nanowire through a process of electrochemical deposition and template-directed growth, placing an n-type inorganic material — lead sulphide (PbS) — between two p-type organic materials, the π-conjugated polymers poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy). In the resulting three-section nanowire, each junction (PEDOT/PbS and PPy/PbS) acts as a diode, only transporting current towards the central PbS rod. When the organic segments are subjected to a voltage input, and the inorganic segment serves as output, the device acts as an ‘or’ logic gate where a non-zero voltage in either, or both, inputs provides a non-zero output. A novel heterojunction structure combining three kinds of semiconductors was designed and fabricated. The heterojunction structure can be used as a two-input OR gate with the combination of two diodes on the two interfaces of the organic/inorganic semiconductor. The research will have great influence in both the fundamental research field of nanoscience and the device application field of nanotechnology.

All-optical logic gates have attracted considerable attention over the past decade. They have found application as adders, subtractors, header recognizers, parity checkers and in encryption systems. In this paper, we present a new structure based on cascaded 4×4 and 2×2 multimode interference (MMI) couplers for implementing optical XOR, XNOR, NAND and OR logic gates. The emphasis of the design is on optimising bandwidth and fabrication tolerance. Such a design would be useful for optical label swapping and recognition in optical packet switching networks. We use silicon on insulator (SOI) waveguides that are compatible with the CMOS technology, for designing the whole device. The Beam Propagation Method (BPM) and the Eigenmode Expansion Method (EEM) are used for numerical simulations. We show that the contrast ratios for logic 1 and logic 0 for XOR, XNOR, NAND, and OR gates are from 18 dB to 28 dB for a bandwidth of 30nm, respectively. A large fabrication tolerance of ±500 nm can be achieved by using this structure.

Programmable photonic circuits (PPCs) are recognized as building blocks for photonic neuromorphic devices and reconfigurable photonic neural networks (PNNs). While traditional PPCs are primarily made of inorganic materials, polymeric materials offer advantages such as mechanical flexibility and a rapid fabrication process at low cost. Here, we demonstrate a fully polymeric PPC constructed only from polydimethylsiloxane (PDMS) doped with the organic dye Rhodamine123. We initially fabricated a Y‐shaped all‐optical logic gate from PDMS and demonstrated its functionality as both an OR and NAND gate. Following this, we fabricated three distinct shapes of PDMS photonic structures and evaluated their performance by injecting amplitude‐modulated optical signals of varying wavelengths and measuring their resulting output signals. By doping one of the PDMS structures (in the shape of a hexagonal mesh) with Rhodamine123 at specific locations and heating the entire structure, we managed to control the intensities of the output optical signals, indicating that temperature serves as a programmable parameter that may regulate the ‘weights’ in a polymer‐organic PNN device. This dual control via doping concentration and temperature introduces a novel method for PPCs made of organic materials. Our findings suggest a promising route toward flexible, low‐cost, and biocompatible photonic neuromorphic hardware leveraging polymer‐organic platforms.

In this article, we propose a common photonic crystal based logic gate structure with T-shaped waveguide which can be used as XOR, OR and NOT gates. The inputs are inphase with each other for OR function whereas they are out of phase for XOR and NOT functions. The destructive interference due to out of phase inputs produces a very low output transmission for logic ‘0’ which leads the structure to provide an output contrast ratio of 55.31 dB. Moreover, compared with the existing literature on the photonic crystal based logic gates, the achieved contrast ratio of the proposed structure is improved by more than 23%. Further, the calculated response time is very less with a value of 0.1456 ps which leads to a bit rate of 6.868 Tbps.

One of the goals in the field of synthetic biology is the construction of cellular computation devices that could function in a manner similar to electronic circuits. To this end, attempts are made to create biological systems that function as logic gates. In this work we present a theoretical quantitative analysis of a synthetic cellular logic-gates system, which has been implemented in cells of the yeast Saccharomyces cerevisiae (Regot et al., 2011). It exploits endogenous MAP kinase signaling pathways. The novelty of the system lies in the compartmentalization of the circuit where all basic logic gates are implemented in independent single cells that can then be cultured together to perform complex logic functions. We have constructed kinetic models of the multicellular IDENTITY, NOT, OR, and IMPLIES logic gates, using both deterministic and stochastic frameworks. All necessary model parameters are taken from literature or estimated based on published kinetic data, in such a way that the resulting models correctly capture important dynamic features of the included mitogen-activated protein kinase pathways. We analyze the models in terms of parameter sensitivity and we discuss possible ways of optimizing the system, e.g., by tuning the culture density. We apply a stochastic modeling approach, which simulates the behavior of whole populations of cells and allows us to investigate the noise generated in the system; we find that the gene expression units are the major sources of noise. Finally, the model is used for the design of system modifications: we show how the current system could be transformed to operate on three discrete values.

In this paper, an all-optical logic gate with multiple functions and asymmetric structure is theoretically designed and simulated using a silicon on insulator (SOI)-based multimode interference (MMI) coupler. By switching the optical signal to different input waveguide ports, the device can function as an OR, NOT, NAND, or NOR gate simultaneously or individually. Simulation results by using three-dimensional beam propagation method (3D-BPM) incorporated with effective index method (EIM) show that these logic gates can operate with low loss in a wide wavelength band as much as 100 nm. It is a kind of promising device for applications on the next-generation high-speed, compact logic circuits, ultrafast signal processing as well as future silicon photonics-based integrated circuits.