Phys.org January 10, 2023 After an extensive study of the angular dependence of quantum oscillations (QOs) in the electrical conductivity of YPtBi an international team of researchers (USA – University of Maryland, Missouri University of Science and Technology, Rutgers University, Canada) has reported an anomalous Shubnikov–de Haas effect consistent with the presence of a coherent j=3/2 Fermi surface. The QO signal in YPtBi manifested an extreme anisotropy upon rotation of the magnetic field from the [100] to [110] crystallographic direction, where the QO amplitude vanished. According to the researchers this radical anisotropy for such a highly isotropic system cannot be […]
Author Archives: Hema Viswanath
Killing Anthrax More Quickly with Hot Air Decontamination
Global Biodefence January 4, 2023 Although the hot air decontamination process is within materials specifications for aircraft, extended hot air exposure may affect sensitive systems. Germination occurs when a bacterial spore develops into a growing, vegetative bacterial cell. While spores are resistant to environmental extremes such as heat, most vegetative bacterial cells are susceptible to higher temperatures, so causing germination and raising ambient temperature is one way kill bacterial spores. Researchers at the Naval Surface Warfare Center Dahlgren Division (NSWC-DD) field tested the bacterial spore germination process by spreading over 100 million human-safe bacterial surrogate for Bacillus anthracis bacterial spores […]
Lithium-sulfur batteries are one step closer to powering the future
Science Daily January 6, 2023 Lithium-sulfur batteries exhibit poor cycle life and low energy content due to the polysulfides shuttling during cycling. An international team of researchers (South Korea, USA – Argonne National Laboratory, Stanford University) developed redox-active interlayers consisting of sulfur-impregnated polar ordered mesoporous silica. Unlike the redox-inactive interlayers, these redox-active interlayers enabled the electrochemical reactivation of the soluble polysulfides, protected the lithium metal electrode from detrimental reactions via silica-polysulfide polar-polar interactions and increased the cell capacity. When tested in a non-aqueous Li-S coin cell configuration, the use of the interlayer enabled an initial discharge capacity of about 8.5 […]
New approach to epidemic modeling could speed up pandemic simulations
Science Daily January 5, 2023 Simulating large-scale epidemics requires substantial computational resources and in many cases is practically infeasible. One way to reduce the computational cost of simulating epidemics on the networks derived from modern datasets is sparsification, where a representative subset of edges is selected based on some measure of their importance. Researchers at Santa Fe Institute used the effective resistance, which takes both local and global connectivity into account. They tested their method in simulations on a U.S.-wide mobility network and fond that it preserved epidemic dynamics with high fidelity. According to the researchers combined with efficient epidemic […]
New nanowire sensors are the next step in the Internet of Things
Phys.og January 6, 2023 Despite intensive research and rapid progress in self-powered gas devices, most reported devices, specifically NO2 sensors for air pollution monitoring, have limited sensitivity, selectivity, and scalability. Researchers in Australia have demonstrated a photovoltaic self-powered NO2 sensor based on axial p–i–n homojunction InP nanowire (NW) arrays, that overcame these limitations. The device was designed by numerical simulation for insights into sensing mechanisms and performance enhancement. Without a power source, the InP NW sensor achieved an 84% sensing response to 1 ppm NO2 and recorded a limit of detection down to the sub-ppb level, with little dependence on […]
New quantum computing architecture could be used to connect large-scale devices
Science Daily January 5, 2023 Quantum information transfer between arbitrary nodes is generally mediated either by photons that propagate between them or by resonantly coupling nearby nodes. The utility is determined by the type of emitter, propagation channel and receiver. Conventional approaches involving propagating microwave photons have limited fidelity due to photon loss and are often unidirectional, whereas architectures that use direct resonant coupling are bidirectional in principle but can generally accommodate only a few local nodes. Researchers at MIT have demonstrated high-fidelity, on-demand, directional, microwave photon emission by using an artificial molecule comprising two superconducting qubits strongly coupled to […]
New spin control method brings billion-qubit quantum chips closer
Phys.org January 12, 2023 The electron spin forms a qubit that is naturally robust to electric fluctuations. However, a common control strategy is the integration of micromagnets to enhance the coupling between spins and electric fields, which, in turn, hampers noise immunity and adds architectural complexity. An international team of researchers (Australia, Japan, Germany, Canada) used switchable interaction between spins and orbital motion of electrons in silicon quantum dots, without a micromagnet. The weak effects of relativistic spin–orbit interaction in silicon were enhanced, leading to a speed up in Rabi frequency by a factor of up to 650 by controlling […]
The optical fiber that keeps data safe even after being twisted or bent
Science Daily January 10, 2023 Topological states enable robust transport within disorder-rich media. However, to exploit topological protection in a length-scalable platform such as optical fiber remains a challenge. Through modeling and experiment a team of researchers in the UK demonstrated that optical fiber hosts topological supermodes across multiple light-guiding cores. They directly measured the photonic winding number invariant characterizing the bulk and observed topological guidance of visible light over meter length scales. The mechanical flexibility of fiber allowed them to reversibly reconfigure the topological state. As the fiber was bent, they found that the edge states first lost their […]
Paper-supported photodetectors
Nanowerk January 5, 2023 An international team of researchers (Spain, Saudi Arabia, China) integrated semiconducting devices on cellulose paper substrate through a simple abrasion technique that yielded high-performance photodetectors. A solvent-free WS2 film deposited on paper favored an effective electron-hole separation and hampered recombination. The prototype photodetectors exhibited a sensitive photoresponse over a wide spectral range spanning from ultraviolet (365 nm) to near-infrared (940 nm). They found that ambient oxygen molecules decreased the photoresponse and stability of the photodetector. By controlling environmental exposure, they were able to increase the performance of the detector. They built a spectrometer using a paper-based […]
Scientists Have Decrypted the “Mechanical Code” of DNA
SciTech Daily January 6, 2023 Diverse DNA-deforming processes are impacted by the local mechanical and structural properties of DNA, which in turn depend on local sequence and epigenetic modifications. Deciphering the mechanical code which impacts the diverse deforming processes has been a challenge. Utilizing high-throughput measurements of DNA bendability an international team of researchers (UK, USA – Johns Hopkins University, Howard Hughes Medical Institute, Spain) quantitatively established how the occurrence and spatial distribution of dinucleotides, tetranucleotides and methylated CpG impact DNA bendability. They used the measurements to develop a physical model for the sequence and methylation dependence of DNA bendability. […]