A new path for electron optics in solid-state systems

Science Daily  July 14, 2020 Electron optics has been demonstrated mainly in one-dimensional devices, for example in nanotubes. Researchers in Switzerland have shown that the band inversion and hybridization present in two coupled semiconductor layers, consisting of InAs and GaSb system provide a novel transport mechanism that guarantees non-vanishing interference even when all angles of incidence occur. Through a combination of transport measurements and theoretical modelling, they found that their devices operate as a Fabry-Pérot interferometer in which electrons and holes form hybrid states. As the mechanism requires only band inversion and hybridization, the research opens engineering electron-optical phenomena in […]

Recognising fake images using frequency analysis

EurekAlert  July 16, 2020 To date, deep-fake images have been analysed using complex statistical methods. Researchers in Germany converted the images into the frequency domain using the discrete cosine transform and express the image as the sum of many different cosine functions. Natural images consist mainly of low-frequency functions. The analysis has shown that images generated by GANs (Generative Adversarial Networks) exhibit artefacts in the high-frequency range. The researchers’ experiments showed that these artefacts do not only occur in GAN generated images. They are a structural problem of all deep learning algorithms. Frequency analysis is therefore an effective way to […]

Scientists build high-performing hybrid solar energy converter

Science Daily  July 15, 2020 A team of researchers in the US (UC San Diego, Tulane University, San Diego State University) has developed a hybrid solar energy converter that generates electricity and steam with high efficiency and low cost. It utilizes an approach that more fully captures the whole spectrum of sunlight. It generates electricity from high efficiency multi-junction solar cells that also redirect infrared rays of sunlight to a thermal receiver, which converts those rays to thermal energy. Energy can be stored until needed. In demonstrations it operated at 85.1 percent efficiency, delivered steam at up to 248°C, and […]

Seventy-Five Years After Trinity

Inside Science  July 15, 2020 The Manhattan Project’s massive effort to build the first atomic bomb led to the Trinity test on July 16, 1945. The project had consumed huge amounts of resources in building weapons of unprecedented potency, gave godlike power to flawed humans. It also inspired innovations and actions that continue to cascade through science and culture in ways both predictable and surprising. The stories, videos and graphics collected here commemorate the 75th anniversary of Trinity and present a snapshot of how deeply the influence of the Manhattan Project has permeated science and culture. While we cannot possibly […]

Tiny bubbles make a quantum leap

EurekAlert  July 13, 2020 An international team of researchers (USA – UC Berkeley, Columbia University, industry, Montana State University, Germany, Japan) found that placing sufficient strain in a 2D material–tungsten diselenide creates localized states that can yield single-photon emitters. The team was able to directly image these states for the first time, revealing that even at room temperature they are highly tunable and act as quantum dots, tightly confined pieces of semiconductors that emit light. Fully tunable, room-temperature single-photon emitters are now within our grasp, paving the way for controllable–and practical quantum photonic devices. These devices can be the foundation […]

UBCO researchers create liquid-repelling substance that works on all surfaces

EurekAlert  July 15, 2020 Omniphobic–all-liquid repellent–films can repel a broad range of liquids, but the applicability of these coatings has always been limited to silicon wafers or smooth glass. Researchers in Canada have developed a facile procedure to generate an omniphobic coating on any surface, including metals, paper, ceramics, etc. The process involves depositing an ultra smooth, silicon wafer-like silica layer and then treating this layer with a highly reactive chlorosilane, which grafts polydimethylsiloxane chains onto the surface. Negligible contact angle hysteresis (≤1°) for various liquids, including ultralow surface tension oils, alcohols, and fluoro-solvents, was achieved on many different substrates […]

Underused part of the electromagnetic spectrum gets optics boost from metamaterial

Phys.org  July 14, 2020 Terahertz radiation potentially has applications in next-generation wireless communications (6G/7G), security systems, biomedicine, etc. because of the lack of appropriate materials and sophisticated optical components for flexible control of terahertz waves. Researchers in Japan have engineered a 2.28-µm ultra-thin terahertz metasurface collimator with a high directivity of 4.6 times consisting of 339 pairs of meta-atoms compared with a single terahertz continuous-wave source. The metasurface exhibits an extremely high refractive index of 15.0 and a low reflectance of 15.5% at 3.0 THz. It should facilitate ground-breaking applications such as arbitrary phase converters, solid immersion lenses, and cloaking…read more. […]

Using magnetic worms to engineer nanoscale communication systems

Nanowerk  July 15, 2020 High-frequency electromagnetic waves are used to transmit and process information in microelectronic devices. To gain a better understanding of precisely the way magnons behave and propagate in different structures researchers in Switzerland examined how electromagnetic waves propagate, and how they could be manipulated, in artificial ferromagnetic quasicrystals. They found that under controlled conditions a single electromagnetic wave coupled to an artificial quasicrystal splits into several spin waves which then propagate within the structure. Each of these spin waves represents a different phase of the original electromagnetic wave, carrying different information. By imaging wavefronts in quasicrystals, insight […]

Top 10 Science and Technology Inventions for the Week of July 10, 2020

01. Magnetic memory states go exponential 02. New biomaterial could shield against harmful radiation 03. Scaling up the quantum chip 04. Harvesting hydrogen from nanogardens 05. Scientists create new device to light up the way for quantum technologies 06. Shining light into the dark: New discovery makes microscopic imaging possible in dark conditions 07. Engineers design a reusable, silicone rubber face mask 08. Physics team observes extremely fast electronic changes in real time in a special material class 09. Porous graphene ribbons doped with nitrogen for electronics and quantum computing 10. Generator developed for harvesting energy from droplets And others… […]

Call for immunology to return to the wild

EurekAlert  July 2, 2020 The viruses that cause COVID-19, AIDS, Ebola, and rabies – among others – all made the lethal jump from wildlife into humans. At the Australian Wild and Comparative Immunology (WACI) https://www.wacimmuno.com/ workshop researchers in Australia outline how integrating a more diverse set of species and environments could enhance the biomedical research cycle. The viruses that cause COVID-19, AIDS, Ebola, and rabies – among others – all made the lethal jump from wildlife into humans. Understanding how the immune system works in animals that live with coronaviruses in a natural environment, such as bats, can give us […]