Phys.org September 18, 2024 In the present United Nations report on contemporary forms of racism, racial discrimination, xenophobia and related intolerance, the author summarizes the activities that she undertook over the past year, and addressed the ways in which the predominant assumption that technology is objective and neutral, is allowing artificial intelligence to perpetuate racial discrimination. She examined four cross-cutting ways in which artificial intelligence can contribute to manifestations of racial discrimination: data problems, algorithm design issues, the intentionally discriminatory use of artificial intelligence and accountability issues. She provided examples of the application of artificial intelligence across various societal domains […]
New method improves understanding of light-wave propagation in anisotropic materials
Phys.org September 17, 2024 Although structurally anisotropic materials are ubiquitous in several application fields, their accurate optical characterization remains challenging due to the lack of general models linking their scattering coefficients to the macroscopic transport observables and the need to combine multiple measurements to retrieve their direction-dependent values. An international team of researchers (Italy, Slovenia, Germany) developed an improved method for the experimental determination of light-transport tensor coefficients from the diffusive rates measured along all three directions, based on transient transmittance measurements and a generalized Monte Carlo model. They applied their method to the characterization of light-transport properties in two […]
Printing 3D photonic crystals that completely block light
Nanowerk September 12, 2024 Fabricating photonic crystals with a complete photonic bandgap in the visible spectrum presents at least two important challenges: achieving a material refractive index > ~2 and a three-dimensional patterning resolution better than ~280 nm. Researchers in Singapore developed a titanium ion-doped resin (Ti-Nano) for high-resolution printing by two-photon polymerization lithography. After printing, the structures were heat-treated in air to induce lattice shrinkage and produced titania nanostructures. The attainted three-dimensional photonic crystals with patterning resolution as high as 180 nm and refractive index of 2.4–2.6. Optical characterization revealed ~100% reflectance within the photonic crystal bandgap in the visible range. They showed […]
Quantum researchers cause controlled ‘wobble’ in the nucleus of a single atom
Phys.org September 12, 2024 The nuclear spin presents opportunities for quantum experiments with prolonged coherence times. Electron spin resonance (ESR) combined with scanning tunnelling microscopy (STM) provides a bottom-up platform to study the fundamental properties of nuclear spins of single atoms on a surface. However, access to the time evolution of nuclear spins remained a challenge. An international team of researchers (The Netherlands, Germany) developed an experiment resolving the nanosecond coherent dynamics of a hyperfine-driven flip-flop interaction between the spin of an individual nucleus and that of an orbiting electron. They used the unique local controllability of the magnetic field […]
Research team uses terahertz pulses of light to shed light on superconducting disorder
Phys.org September 16, 2024 Inhomogeneities crucially influence the properties of quantum materials, yet methods that can measure them remain limited and can access only a fraction of relevant observables. However, complementary techniques that can resolve higher-order correlations are needed to elucidate the nature of the inhomogeneities. And local tunnelling probes are often effective only far below the critical temperature. An international team of researchers (Germany, USA – Brookhaven, Harvard University, Cornell University, Stony Brook University, Switzerland, UK) developed a two-dimensional terahertz spectroscopy method to measure Josephson plasmon echoes from an interlayer superconducting tunnelling resonance in a near-optimally doped cuprate. The […]
This screen stores and displays encrypted images without electronics
Nanowerk September 17, 2024 While computation functions have been demonstrated in mechanical systems, they rely on compliant mechanisms to achieve predefined states, which impose inherent design restrictions that limit their miniaturization, deployment, reconfigurability, and functionality. Researchers at the University of Michigan describe a metamaterial system based on responsive magnetoactive Janus particle (MAJP) swarms with multiple programmable functions. They designed MAJPs with tunable structure and properties in mind, that is, encoded swarming behavior and fully reversible switching mechanisms, to enable programmable dynamic display, non-volatile and semi-volatile memory, Boolean logic, and information encryption functions in soft, wearable devices. According to the researchers […]
The skyscraper-sized tsunami that vibrated through the entire planet and no one saw
Phys.org September 14, 2024 A large rockslide occurred in Greenland on 16 September 2023 that generated a local tsunami. The event was energetic enough to generate a global signal that resonated for 9 days. An international team of researchers (Denmark, UK, Germany, Belgium, France, USA – USGS, UC Berkeley, UC San Diego, UC Riverside, Boston College, University of Washington, Norway, The Netherlands, Italy, Sweden, Spain, Costa Rica, New Zealand, Indonesia, Greenland) detected the start of a 9-day-long, global 10.88-millihertz (92-second) monochromatic very-long-period (VLP) seismic signal, originating from East Greenland. They demonstrated how this event started with a glacial thinning–induced rock-ice […]
Why the next pandemic could come from the Arctic — and what to do about it
Nature, 04 September 2024 Between 1979 and 2021, the region warmed four times faster than the global average. Its ability to store carbon and weather patterns are poorly understood. According to the researchers in Denmark in addition to the effects of biodiversity loss and pollution, and people, as the Arctic warms, its environment degrades and human activities increase, new health threats are emerging leading to a quadruple crisis. Since starting research in the Arctic in 1997, monitoring changes in pollution levels, habitats and food webs using a ‘One Health’ approach that integrates effects on wildlife, humans and ecosystems, the Arctic […]
Top 10 Science and Technology Inventions for the Week of September 13, 2024
01. Researchers make sound waves travel in one direction only, with implications for electromagnetic wave technology 02. Atoms on the edge 03. Dozens of viruses detected in Chinese fur farm animals 04. Composite plastic degrades easily with bacteria, offers environmental benefits 05. Extreme weather to strengthen rapidly over next two decades, research suggests 06. Molecular simulations and supercomputing shed light on energy-saving biomaterials 07. Sweeping global study charts a path forward for climate-resilient agriculture 08. New quantum error correction method uses ‘many-hypercube codes’ while exhibiting beautiful geometry 09. Scientists uncover hidden source of snow melt: Dark brown carbon 10. Optoelectronic […]
Atoms on the edge
MIT News September 6, 2024 The chiral edge modes lie at the heart of the integer and fractional quantum Hall effects, and their robustness against noise and disorder reflects the quantization of Hall conductivity in these systems. Despite their importance, the controllable injection of edge modes, and direct imaging of their propagation, structure and dynamics, remains challenging. Researchers at MIT demonstrated the distillation of chiral edge modes in a rapidly rotating bosonic superfluid confined by an optical boundary. By tuning the wall sharpness they revealed the smooth crossover between soft wall behaviour in which the propagation speed was proportional to […]