Phys.org April 4, 2024 Moiré-pattern-based potential engineering has become an important way to explore exotic physics in a variety of two-dimensional condensed matter systems. An international team of researchers (Spain, Singapore) demonstrated theoretically that a single layer of graphene, when placed between two bulk boron nitride crystal substrates with the appropriate twist angles, could support a robust topological ultra flat band emerging as the second hole band. According to the researchers this is one of the simplest platforms to design and exploit topological flat bands… read more. TECHNICAL ARTICLE
Author Archives: Hema Viswanath
Waterproof ‘e-glove’ could help scuba divers communicate
Nanowerk April 10, 2024 Existing tactile sensing gloves fall short in terms of user comfort and are ill-suited for underwater applications. Researchers in China proposed and constructed a flexible hand gesture recognition glove (GRG) that contained high-performance micropillar tactile sensors (MPTSs) inspired by the flexible tube foot of a starfish. The sensor has a wide working range, superfast response time, reliable repeatability, and a low limit of detection and they were waterproof. When integrated with machine learning algorithm, the GRG system achieved intelligent recognition of 16 hand gestures under water, extending real-time and effective communication capabilities for divers. According to […]
Top 10 Science and Technology Inventions for the Week of April 05, 2024
01. 100 kilometers of quantum-encrypted transfer 02. Intelligent liquid 03. Magnetic avalanche triggered by quantum effects: ‘Barkhausen noise’ detected for first time 04. New hydrogel can stretch to 15 times its original size 05. Researchers discover dual topological phases in an intrinsic monolayer crystal 06. Room-temperature 2D magnet: Electronic-structure insights 07. ‘Shear sound waves’ provide the magic for linking ultrasound and magnetic waves 08. A solar cell you can bend and soak in water 09. Universal brain-computer interface lets people play games with just their thoughts 10. A simple way to harvest more ‘blue energy’ from waves And others Atmospheric […]
100 kilometers of quantum-encrypted transfer
Phys.org April 2, 2024 Continuous-variable (CV) quantum key distribution (QKD) with coherent states and coherent detection integrates well with existing telecommunication networks. Thus far, long-distance CV-QKD has only been demonstrated using a highly complex scheme where the local oscillator is transmitted, opening security loopholes for eavesdroppers, and limiting potential applications. Researchers in Denmark have demonstrated a long-distance CV-QKD experiment with a locally generated oscillator over a 100-kilometer fiber channel with a total loss of 15.4 decibels. This was done by controlling the phase noise–induced excess noise through a machine learning framework for carrier recovery and optimizing the modulation variance. They […]
Atmospheric observations in China show rise in emissions of a potent greenhouse gas
MIT News March 28, 2024 An international team of researchers (USA – MIT, NOAA, UC San Diego, China, UK, Australia) used long-term atmospheric observations to determine SF6 emissions from China between 2011 and 2021 to evaluate the Chinese national SF6 emission inventory and to better understand the global SF6 budget. SF6 emissions in China substantially increased in 2021. The increase was larger than the global total emissions rise. Emissions in the less-populated western regions of China contributed significantly to the national SF6 emissions. The CO2-eq emissions of SF6 in China in 2021 were 125 million tonnes, comparable to the national […]
Intelligent liquid
Nanowerk April 4, 2024 Traditionally the building blocks of metamaterials are arranged in fixed positions within a lattice structure. An international team of researchers (USA – Harvard University, Israel) showed that by mixing highly deformable spherical capsules into an incompressible fluid, it is possible to realize a ‘metafluid’ with programmable compressibility, optical behaviour, and viscosity. Experimentally and numerically, they demonstrated that the buckling of the shells endows the fluid with a highly nonlinear behaviour. They harnessed this behaviour to develop smart robotic systems, highly tunable logic gates and optical elements with switchable characteristics. They demonstrated that the collapse of the […]
Magnetic avalanche triggered by quantum effects: ‘Barkhausen noise’ detected for first time
Phys.org March 28, 2024 Most macroscopic magnetic phenomena (including magnetic hysteresis) are typically understood classically. An international team of researchers (USA – Caltech, University of Colorado, University of Chicago, University of Tennessee, Canada, Japan, UK) examined the dynamics of a uniaxial rare-earth ferromagnet deep within the quantum regime, so that domain wall motion, and the associated hysteresis, was initiated by quantum nucleation, which then grew into large-scale domain wall motion, that was observable as an unusual form of Barkhausen noise. They found that the “quantum Barkhausen noise” exhibited two distinct mechanisms for domain wall movement, each of which was quantum-mechanical, […]
New hydrogel can stretch to 15 times its original size
Phys.org March 29, 2024 Hyper elastic materials exhibit a nonlinear elastic response to large strains, whereas hydrogels typically possess a low elastic range due to the nonuniform cross-linking and limited chain segments among cross-links. An international team of researchers (USA, China) developed a hyperplastic hydrogel that possesses a broader elastic range by introducing a reversible pearl-necklace structure, in which beads are connected by strings. The subnanometric beads could efficiently unfold and refold under cyclic mechanical strains; thus, the hydrogel could rapidly recover after being stretched to an aerial strain of more than 10,000%. It could quickly heal from minor mechanical […]
Research team realizes magnonic frequency comb
Phys.org April 1, 2024 A direct analog of frequency combs in the magnonic systems has not been demonstrated to date. Researchers in China generated a new magnonic frequency comb in the resonator with giant mechanical oscillations through the magnomechanical interaction. It contained up to 20 comb lines, which were separated by the mechanical frequency of 10.08 MHz. The thermal effect based on the strong pump power induced the cyclic oscillation of the magnon frequency shift, which led to a periodic oscillation of the magnonic frequency comb. They demonstrated the stabilization and control of the frequency spacing of the magnonic frequency […]
Researchers determine structure of new metal tellurate material with potential uses in solar energy and more
Phys.org April 3, 2024 An international team of researchers (Austria, Sweden, Canada, Finland) grew crystals of CoTeO4 crystals by the application of chemical vapor transport reactions in closed silica ampoules, starting from polycrystalline material in a temperature gradient with TeCl4 as transport agent. Crystal structure analysis of CoTeO4 showed noticeable improvement over the statistical significance and accuracy of the previously reported structural model. CoTeO4 did not undergo a structural phase transition upon heating, but decomposed stepwise (Co2Te3O8 as intermediate phase) to Co3TeO6 as the only crystalline phase stable above 770 °C. Temperature-dependent magnetic susceptibility and dielectric measurements suggested antiferromagnetic ordering […]