Phys.org October 2, 2024 Optically addressable spin defects in 3D crystals and 2D van der Waals (vdW) materials are important for nanoscale quantum sensing. However, optically detected magnetic resonance of localized spin defects in a nanotube has not been observed. A team of researchers in the US (Purdue University, Indiana University) found single spin color centers in boron nitride nanotubes (BNNTs) at room temperature which suggested that BNNT spin defects possess a spin S = 1/2 ground state without an intrinsic quantization axis, leading to orientation-independent magnetic field sensing. Using this unique feature, they observed anisotropic magnetization of a 2D […]
Researchers observe hidden deformations in complex light fields
Phys.org October 1, 2024 When reflected from an interface, a laser beam generally drifts and tilts away from the path predicted by ray optics, an intriguing consequence of its finite transverse extent. For twisted light, such beam shifts manifest even more dramatically: upon reflection, a field containing a high-order optical vortex is expected to experience not only geometrical shifts, but an additional splitting of its high-order vortex into a constellation of unit-charge vortices, a phenomenon known as topological aberration. In an experiment an international team of researchers (Finland, Brazil) observed topological aberration effect verified through the deformation of vortex constellations […]
Scientists demonstrate advanced low-coherence BOCDR system using periodic pseudo-random modulation
Phys.org October 1, 2024 Brillouin optical correlation-domain reflectometry (BOCDR) is a technique for measuring the distribution of strain and temperature along an optical fiber. However, it faces a trade-off between spatial resolution and measurement range. Researchers in Japan proposed low-coherence BOCDR based on periodic pseudo-random modulation to address this issue and demonstrated its proof-of-concept operation. First, the dependence of the light source output spectrum on modulation parameters was investigated showing the potential to resolve the trade-off between spatial resolution and measurement range. They also demonstrated the capability of measuring strain distribution along optical fibers without a variable delay line under […]
Scientists uncover light absorbing properties of achiral materials
Phys.org September 30, 2024 In chiral metasurfaces, the lack of symmetry leads to differential absorption when probed with chiral light either in the form of circular polarization or helical phase fronts. Researchers in Canada demonstrated differential absorption of asymmetric twisted light beams, known as helical dichroism, which exist in an array and a single achiral structure and could be controlled. When extended to chiral structures, these asymmetrical chiral light modes enabled enhancing and tuning chiroptical sensitivity. According to the researchers their technique offers more control parameters than just changing the OAM value. Selective response to asymmetric helical light beams was […]
Solid electrolyte composed of nanoparticles shows promise for all-solid-state batteries
Phys.org October 2, 2024 Halide solid electrolytes are promising for improving the electrochemical performance of all-solid-state batteries. However, the state-of-the-art sodium-ion-conducting halides are not as high in conductivity as expected and lack reduction stability. Researchers in Japan found oxychlorides in a ternary system NaCl–TaCl5–Ta2O5 have high conductivities, formabilities, and oxidation and reduction stabilities. They mechanochemically prepared samples composed of NaCl and Ta2O5 nanoparticles embedded in an Na–Ta–Cl–O amorphous matrix, possessing ionic conductivities of 2.5 × 10–3 S cm–1 at 25 °C and electrochemical potential windows of 0.4–4.1 versus Na+/Na. Compression tests revealed that the nanoparticles in the oxychloride electrolytes improved […]
Why the gender gap in physics has been stable for more than a century
Phys.org September 26, 2024 Social and technical networks undergo constant evolution driven by both existing entities and newcomers. In academia, research papers are continually cited by new papers, while senior researchers integrate newly arrived junior researchers into their academic networks. Moreover, social systems can be influenced by external factors that could indirectly impact their growth patterns. For instance, systematic discrimination against certain groups in academia or managerial positions can impede their long-term growth, especially when combined with group-level preferences in hiring or adoption, as observed in our study. An international team of researchers (Germany, Austria) introduced a network growth and […]
Top 10 Science and Technology Inventions for the Week of September 27, 2024
01. First liquid-liquid extraction trial finds porous liquids can separate harmful or unwanted alcohols from mixtures 02. Light momentum turns pure silicon from an indirect to a direct bandgap semiconductor 03. New material with wavy layers of atoms exhibits unusual superconducting properties 04. Novel computational method addresses obstacles in phonon-based heat simulation 05. Physicists use quantum correlations of photon pairs to hide images from standard cameras 06. Researchers observe an antiferromagnetic diode effect in even-layered MnBi₂Te₄ 07. Thermal effects in spintronics systematically assessed for first time 08. High-pressure reactions can turn nonporous rocks into sponges 09. Engineers 3D print sturdy […]
Arctic warming may fuel ice formation in clouds, observations suggest
Phys.org September 19, 2024 The roles of Arctic aerosols as ice-nucleating particles are crucial for assessing the climate sensitivity of Arctic mixed-phase clouds and predicting their response to Arctic warming. An international team of researchers (Japan, Norway) presented a full-year record of ice-nucleating particle concentrations over Svalbard, where surface warming has been anomalously faster than the Arctic average. While the variation of ice-nucleating particles active at around −30 °C was relatively small, those active at higher temperatures tended to increase exponentially with rising surface air temperatures when the surface air temperatures rose above 0 °C and snow/ice-free barren and vegetated areas appeared […]
Atmospheric methane increase during pandemic due primarily to wetland flooding, satellite data analysis finds
Phys.org September 24, 2024 The causes for the rapid rise of atmospheric methane concentrations over the past decade have been unclear. An international team of researchers (USA – Harvard University, Jet Propulsion Laboratory, UK) found that emissions from the wet tropics drove the 2010–2019 increase and the subsequent 2020–2022 surge, while emissions from northern mid-latitudes decreased. The 2020–2022 surge was principally contributed by emissions in Equatorial Asia and Africa. Wetlands were the major drivers of the 2020–2022 emission increases in Africa and Equatorial Asia because of tropical inundation associated with La Niña conditions, consistent with trends in the GRACE terrestrial […]
Climate models predict abrupt intensification of northern wildfires due to permafrost thawing
Phys.org September 24, 2024 Climate change will accelerate Arctic-Subarctic permafrost thaw which can intensify microbial degradation of carbon-rich soils, methane emissions, and global warming. To better understand the impact of permafrost thaw on future Arctic-Subarctic wildfires and the associated release of greenhouse gases and aerosols an international team of researchers (South Korea, Japan, Norway, USA – National Center for Atmospheric Research, University of Colorado) presented a comprehensive analysis of the effect of future permafrost thaw on land surface processes in the Arctic-Subarctic region using large ensemble forced by the SSP3-7.0 greenhouse gas emission scenario. Analyzing 50 greenhouse warming simulations, which […]