EurekAlert May 19, 2020 In the past, human-caused seismic signals, as a result of industrial activities, were viewed as ‘noise’ that polluted a dataset, resulting in otherwise useful data being dismissed. A team of researchers in the US (Los Alamos National Laboratory, University of Washington) used a year’s worth of data from more than 1,700 seismic stations in the contiguous United States and detected approximately 1.5 million industrial noise sequences, which corresponds on average to around 2.4 detections per day at each station. With cloud computing that allows for greater scalability and flexibility, they were able to analyze large-scale seismic […]
NIST team builds hybrid quantum system by entangling molecule with atom
Phys.org May 20, 2020 Building on the their 2017 demonstration of quantum control of a molecule, a team of researchers in the US (NIST, University of Colorado) successfully entangled two energy levels of a calcium atomic ion with two different pairs of rotational states of a calcium hydride molecular ion, which is a calcium ion bonded to a hydrogen atom. The molecular qubit had a transition frequency—the speed of cycling between two rotational states—of either low energy at 13.4 kilohertz (kHz, thousands of cycles per second) or high energy at 855 billion cycles per second (gigahertz or GHz). Molecules could […]
Observation of intervalley transitions can boost valleytronic science and technology
Science Daily May 15, 2020 When monolayer WSe2 absorbs a photon, a bound electron can be freed in a valley, leaving behind a hole resulting in an exiton. This is called an intravalley exciton which can emit light. The law of momentum conservation, however, forbids an electron and a hole in opposite valleys from recombining directly to emit light. As a result, intervalley excitons are “dark” and hidden in the optical spectrum. An international team of researchers (USA – UC Riverside, Taiwan, Japan) found that although the intervalley excitons are intrinsically dark, they can emit circularly polarized light. The optically […]
Quantum leap: Photon discovery is a major step toward at-scale quantum technologies
EurekAlert May 20, 2020 Architectures for photonic quantum computing place stringent demands on high quality information carriers. An international team of researchers (UK, Italy) has fabricated on-chip photon sources and demonstrated that they meet the computing requirements. The photon sources are fabricated in silicon using mature processes and exploit a dual-mode pump-delayed excitation scheme to engineer the emission of spectrally pure photon pairs through inter-modal spontaneous four-wave mixing in low-loss spiraled multi-mode waveguides. They measured a spectral purity of 0.9904 ± 0.0006, a mutual indistinguishability of 0.987 ± 0.002, and >90% intrinsic heralding efficiency and on-chip quantum interference with a visibility of 0.96 ± 0.02 between […]
Seeing the invisible: Polarizer adjustments increase visibility of transparent objects
Phys.org May 19, 2020 In biological microscopy and X-ray imaging, many transparent objects or structures are difficult to observe due to their low absorption of light. Researchers in China have demonstrated that adjusting the polarizers can optically compute the spatial differentiation of the incident light field along different directions. They improved contrast by tuning a uniform constant background as a bias, creating a virtual light source that casts a shadow on the measured images. Based on this bias approach, they can distinguish the phase increases and decreases in light field distribution and quantify the optical thickness of observed objects with […]
Sneakier and More Sophisticated Malware Is On the Loose
IEEE Spectrum May 18, 2020 To understand how Android malware has evolved over time, an international team of researchers (US, USA – Boston University) analyzed over 1.2 million malware samples that belonged to 1.28K families over a period of eight years (from 2010 to 2017). The analysis framework relied on collective repositories and recent advances on the systematization of intelligence extracted from multiple anti-virus vendors using differential analysis to isolate software components that are irrelevant to the campaign and studied the behavior of malicious riders alone. They found that since its infancy in 2010, the Android malware ecosystem has changed […]
A system for robust and efficient wireless power transfer
Phys.org May 18, 2020 Wireless power transfer set-ups typically suffer from an inherent sensitivity to the relative movement of the device with respect to the power source. Previous implementations to deliver robust wireless power transfer even while a device is moving rapidly have relied on an inefficient gain element based on an operation-amplifier circuit, which has inherent loss, and hence have exhibited poor total system efficiency. Researchers at Stanford University have shown that robust and efficient wireless power transfer can be achieved by using a power-efficient switch-mode amplifier with current-sensing feedback in a parity–time symmetric circuit. The parity–time symmetry guarantees […]
‘Tantalizing’ clues about why a mysterious material switches from conductor to insulator
Nanowerk May 18, 2020 Researchers in Japan created crystals of tantalum disulfide and then cleaved the crystals in a vacuum to reveal ultra-clean surfaces which they examined, at a temperature close to absolute zero. Using quantum tunneling they studied the degree of conducting behavior of the material. The results showed that there was indeed a stacking of layers which effectively arranged them into pairs. Sometimes the crystals cleaved between the pairs of layers, and sometimes through a pair, breaking it. They performed spectroscopy on both the paired and unpaired layers and found that even the unpaired ones are insulating, leaving […]
Using the ‘shadow effect’ to generate electricity
Techxplore May 21, 2020 Researchers in Singapore used Kelvin Probe Force Microscopy to experimentally validated that a shadow-effect energy generator (SEG) scavenges the illumination contrast that arises on the device from shadow castings, and generates a direct current, simply by placing a part of the generator in shadow. The SEG is capable of harvesting energy from illumination contrasts arising under weak ambient light. Without any optimization, the generator has a power density of 0.14 μW cm−2 under indoor conditions 0.001 sun, where shadows are persistent. It performs 200% better than that of commercial silicon solar cells under the effects of […]
Top 10 Science and Technology Inventions for the Week of May 15, 2020
01. Scientists demonstrate quantum radar prototype 02. Engineers Unveil a System That Delivers Electricity Wirelessly – To a Moving Target 03. Making quantum ‘waves’ in ultrathin materials 04. NIST scientists create new recipe for single-atom transistors 05. Seeing Through Opaque Media 06. Room-temperature superionic conduction achieved using pseudorotation of hydride complexes 07. The observation of photon-assisted tunneling signatures in Majorana wires 08. Transporting energy through a single molecular nanowire 09. Potentially fatal combinations of humidity and heat are emerging across the globe 10. COVIDScholar: AI Tool Sifts Through Thousands of Papers to Guide Researchers And others… Anti-Vaccine Messaging Is Well-Connected […]