MIT News December 2, 2024 Optical systems can perform linear matrix operations at an exceptionally high rate and efficiency. However, demonstrating coherent, ultralow-latency optical processing of deep neural networks has remained an outstanding challenge. A team of researchers in the US (MIT, industries) realized such a system in a scalable photonic integrated circuit that monolithically integrated multiple coherent optical processor units for matrix algebra and nonlinear activation functions into a single chip and experimentally demonstrated fully integrated coherent optical neural network architecture for a deep neural network with six neurons and three layers that optically computed both linear and nonlinear […]
Tag Archives: S&T USA
Researchers demonstrate self-assembling electronics
Nanowerk December 2, 2024 Conventional multi-scale array fabrication techniques are facing challenges in reconciling the contradiction between better device performance and lowering the fabrication cost and/or energy consumption. A team of researchers in the US (North Carolina State University, Iowa State University) used facile mixed-metal array fabrication method based on guided self-assembly of polymerizing organometallic adducts derived from the passivating oxides of a ternary liquid metal, to create mixed metal wires. They fabricated large-area, high-quality organometallic nano- to micro-wire arrays without compromising wire continuity or array periodicity. Using capillary bridges on a preceding layer, they made hierarchical arrays with complex […]
Engineers knit a ‘blanket’ of sophisticated radio-frequency antennas
Nanowerk November 27, 2024 Lightweight, low-cost metasurfaces and reflect arrays that are easy to stow and deploy are desirable for many terrestrial and space-based communications and sensing applications. A team of researchers in the US ( Columbia University, North Carolina State University, City University of New York) demonstrated a lightweight, flexible metasurface platform based on flat-knit textiles operating in the cm-wave spectral range. By using float-jacquard knitting to directly integrate an array of resonant metallic antennas into a textile, two textile reflect array devices, a metasurface lens (metalens), and a vortex-beam generator were realized. Operating as a receiving antenna, the […]
Enormous cache of rare earth elements hidden inside coal ash waste, study suggests
Phys.org November 19, 2024 The renewable energy industry is heavily reliant on rare earth elements. A team of researchers in the US (UT Austin, University of Kentucky, University of Wyoming, industry) estimated coal ash resources and potential for extraction of rare earth elements using data for the US. According to the data ~ 52 gigatons (Gt) of coal was produced in the US (1950–2021). Power plants account for most of the coal use. About 70% of coal ash was potentially accessible for rare earth element extraction (1985–2021) and was disposed in landfills and ponds with the remaining coal ash was used […]
Tunable ultrasound propagation in microscale metamaterials
MIT News November 20, 2024 Challenges in miniaturizing and characterizing acoustic metamaterials in high-frequency (megahertz) regimes have hindered progress toward experimentally implementing ultrasonic-wave control. A team of researchers in the US (MIT, Kansas City National Security Campus) presented an inertia design framework based on positioning microspheres to tune responses of 3D microscale metamaterials. They demonstrated tunable quasi-static stiffness by up to 75% and dynamic longitudinal-wave velocities by up to 25% while maintaining identical material density. The researchers explored the tunable static and elastodynamic property relation. According to the researchers their design framework expands the quasi-static and dynamic metamaterial property space […]
Can robots learn from machine dreams?
MIT News November 19, 2024 Fast and accurate physics simulation is an essential component of robot learning, where robots can explore failure scenarios that are difficult to produce in the real world and learn from unlimited on-policy data. Yet, it remains challenging to incorporate RGB-color perception into the sim-to-real pipeline that matches the real world in its richness and realism. Researchers at MIT trained a robot dog in simulation for visual parkour. They proposed a way to use generative models to synthesize diverse and physically accurate image sequences of the scene from the robot’s ego-centric perspective. They presented demonstrations of […]
How can electrons split into fractions of themselves?
MIT News November 18, 2024 Recent experiments on the moiré structure formed by pentalayer rhombohedral graphene aligned with a hexagonal boron nitride substrate report the discovery of a zero-field fractional quantum Hall effect. These “(fractional) quantum anomalous Hall” [(F)QAH] phases occur for one sign of a perpendicular displacement field, and correspond, experimentally, to full or partial filling of a valley polarized Chern-1 band. Such a band is absent in the noninteracting band structure. Researchers at MIT showed that electron-electron interactions play a crucial role, and presented microscopic theoretical calculations demonstrating the emergence of a nearly flat, isolated, Chern-1 band and […]
Idea thieves tend to target early concepts, experiments find
Phys.org November 20, 2024 Creators often encounter the threat of idea theft, which can discourage them from sharing their ideas and receiving vital feedback. A team of researchers in the US (University of Virginia, Cornell University) explored the psychology behind creators’ attempts to strategically manage idea sharing. Across three studies, they found that creators mis-predict the preferences of idea thieves, such that idea thieves prefer to steal ideas in earlier stages of development than creators expect. They found this difference was driven by creators’ tendency to underestimate how much idea thieves attend to moral concerns while deciding when to steal […]
Invisible touch: Researchers give AI the ability to feel and measure surfaces
Phys.org November 18, 2024 Researchers at Stevens Institute explored a novel approach to surface roughness metrology utilizing a single pixel, raster scanning single photon counting LiDAR system. It used a collimated laser beam in picosecond pulses to probe a surface, capturing the changes of back-scattered photons from different points on the surface into a single mode fiber, and counted them using a single photon detector. The back-scattered photons carried speckle noise produced by the rough surface, and the variation in photon counts over different illumination points across the surface becoming a good measure of its roughness. By analyzing the variation […]
MIT physicists predict exotic form of matter with potential for quantum computing
MIT News November 18, 2024 Based on the recent discovery of fractional quantum anomalous Hall states in moiré systems, researchers at MIT studied a family of moiré systems, skyrmion Chern band models, which could be realized in two-dimensional semiconductor-magnet heterostructures and capture the essence of twisted transition metal dichalcogenide homobilayers. Using many-body exact diagonalization they showed that, despite strong Berry curvature variations in momentum space, the non-Abelian Moore-Read state could be realized at half filling of the second miniband. According to the researchers, their results demonstrate the feasibility of non-Abelian fractionalization in moiré systems without Landau levels and shed light […]