EurekAlert March 8, 2021 Critical challenges for real-world applications of flat optics technology are due to the limited operational efficiency in the visible region, on average lower than 60%, which originates from absorption losses in wavelength-thick structures and the realization of on-demand optical components for controlling vectorial light at visible frequencies simultaneously in both reflection and transmission and with a predetermined wavefront shape. Researcher in Saudi Arabia have developed an inverse design approach that allows the realization of highly efficient (up to 99%) ultrathin (down to 50 nm thick) optics for vectorial light control with broadband input–output responses in the visible […]
Author Archives: Hema Viswanath
Linear systems are the workhorse of modern computation
Quanta Magazine March 8, 2021 For solving linear systems researchers at the Georgia Institute of Technology have developed a technique that employs an enhanced version of the iterated guessing strategy: Instead of making just a single guess, their algorithm makes many guesses in parallel. This approach speeds up the search. The key feature to the algorithm’s ultimate success is that it makes the three initial guesses at random. Randomness ensures you do not accidentally end up biasing your search toward one part of the problem, potentially neglecting the space where the actual solution lies. They showed that the different strands […]
Microchips of the future: Suitable insulators are still missing
Nanowerk March 9, 2021 The demands placed by CMOS logic circuits at their ultimate scaling limits could be satisfied by a number of layered 2D materials. Hexagonal boron nitride (hBN) is widely considered to be the most promising gate insulator for meeting challenging requirements for gate insulators. An international team of researchers (Austria, Russia, Switzerland, Japan, Saudi Arabia) assess the material parameters and performance limits of hBN. They compared experimental and theoretical tunnel currents through ultrathin layers of hBN and other 2D gate insulators, including the ideal case of defect-free hBN. Though its properties make hBN a candidate for many […]
Microwave-assisted recording technology promises high-density hard disk performance
Science Daily March 9, 2021 Researchers in Japan analyzed the operation of the flux-control (FC) device by measuring the temporal resistance change in the sub-nanosecond region. They showed that the reversal of the FC device becomes faster as the bias current is increased and can be completed by 0.5 ns after the transition of the write current. They reproduced the experimental results by micromagnetic simulations using a head model, confirming that the simulations correctly describe the magnetization dynamics of the actual device. The simulations showed that the recording field gain by the FC device appears with little delay after the rise […]
New quantum theory heats up thermodynamic research
Phys.org March 5, 2021 The classical Gibbs paradox concerns the entropy change upon mixing two gases. Whether an observer assigns an entropy increase to the process depends on their ability to distinguish the gases. Moving the thought experiment into the quantum realm researchers in the UK have shown that the ignorant observer can extract work from mixing different gases, even if the gases cannot be directly distinguished. In the macroscopic limit, the quantum case diverges from the classical ideal gas: as much work can be extracted as if the gases were fully distinguishable. They showed that the ignorant observer assigns […]
New research could boost a solar-powered fuel made by splitting water
Science Daily March 10, 2021 Altering crystal facets exposed on the surface of photoelectrodes used for solar fuel production has been a major strategy for optimizing their properties. There are numerous ways to terminate the surface even for the same facet, which can considerably alter the photoelectrode properties. A team of researchers in the US (University of Wisconsin, University of Chicago, Brookhaven National Laboratory, Stony Brook University, Argonne National Laboratory) investigated using tightly integrated experimental and computational investigations of epitaxial BiVO4 photoelectrodes with vanadium- and bismuth-rich (010) facets. The study demonstrated that even for the same facet the surface Bi:V […]
Not-for-profit publisher makes big move toward open access science
EurekAlert March 10, 2021 Canadian Science Publishing (CSP)–a not-for-profit publisher of peer-reviewed STEM journals announced a new open access publishing agreement with the University of California (UC) that will offer unlimited open access publication for UC researchers publishing with its journals. CSP is exploring how to shift from subscription-based business models to models that make it easier and more affordable for researchers to publish their work as open access. Under the cost sharing model, the UC libraries will automatically pay the first $1,000 of the article processing charge (APC) for all UC authors who choose to publish in a CSP journal. […]
Reemergence of Human Monkeypox and Declining Population Immunity in the Context of Urbanization, Nigeria, 2017–2020
Global Biodefense March 9, 2021 Using the monkeypox outbreak in Nigeria during 2017–2020 researchers in Australia built a statistical model to simulate declining immunity from monkeypox at 2 levels: At the individual level, they used a constant rate of decline in immunity of 1.29% per year as smallpox vaccination rates fell. At the population level, the cohort of vaccinated residents decreased over time because of deaths and births. By 2016, only 10.1% of the total population in Nigeria was vaccinated against smallpox; the serologic immunity level was 25.7% among vaccinated persons and 2.6% in the overall population. The substantial resurgence […]
Researchers virtually open and read sealed historic letters
MIT News March 2, 2021 Computational flattening algorithms have been successfully applied to X-ray microtomography scans of damaged historical documents, but have so far been limited to scrolls, books, and documents with one or two folds. An international team of researchers (US -MIT, industry, UK, the Netherlands) used automated computational flattening algorithm to read an unopened letter from early modern Europe without breaking its seal or damaging it in any way. They reconstructed the intricate folds, tucks, and slits of unopened letters secured shut with “letterlocking,” a practice—systematized in this paper—which underpinned global communications security for centuries before modern envelopes. […]
Scientists have synthesized a new high-temperature superconductor
Phys.org March 10, 2021 An international team of researchers (Russia, USA – University of Chicago, Spain, Italy, China) performed theoretical and experimental research on yttrium hydride (YH6), one among the three highest-temperature superconductors known to date. All these hydrides reach their maximum superconductivity temperatures at very high pressures. The current challenge is to attain room-temperature superconductivity at lower pressures. In the case of YH6, the agreement between theory and experiment is rather poor. For example, the critical magnetic field observed in the experiment is 2 to 2.5 times greater as compared to theoretical predictions. This is the first-time scientists encounter such […]