Photons can enable real-time physical random bit generation for information security app

Phys.org  May 6, 2022 Most optical-chaos-based random bit generators perform their quantization process in the electrical domain using electrical analog-to-digital converters, so their real-time rates in a single channel are severely limited at the level of Gb/s due to the electronic bottleneck. An international team of researchers (China, UK) has experimentally demonstrated an all-optical method for random bit generation where chaotic pulses are quantized into a physical random bit stream in the all-optical domain by means of a length of highly nonlinear fiber. Using their method, they generated a 10-Gb/s random bit stream on-line. The single-channel real-time rate is limited […]

Physicists Developed a Superconductor Circuit Long Thought to Be Impossible

Science   Alert April 27, 2022 An international team of researchers (Germany, China, the Netherlands, USA – Johns Hopkins University) fabricated an inversion symmetry breaking van der Waals heterostructure of NbSe2/Nb3Br8/NbSe2. They demonstrated that even without a magnetic field, the junction can be superconducting with a positive current while being resistive with a negative current. The ΔIc behaviour (the difference between positive and negative critical currents) with magnetic field is symmetric and Josephson coupling was proved through the Fraunhofer pattern. They achieved stable half-wave rectification of a square-wave excitation with a very low switching current density, high rectification ratio and high […]

Team demonstrates rare form of electricity in ultra-thin material

Phys.org  April 27, 2022 Molybdenum disulfide (MoS2) is known as one of the most promising and robust 2D electronic materials. However, despite theoretical predictions, no ferroelectricity has been experimentally detected in MoS2. An international team of researchers (USA – University of Nebraska, industry, China, France, Luxembourg) has reported the experimental observation of a stable room-temperature out-of-plane polarization ordering in 2D MoS2 layers, where polarization switching is realized by mechanical pressure induced by a tip of a scanning probe microscope. Using this approach, they created the bi-domain polarization states, which exhibit different piezoelectric activity, second harmonic generation, surface potential, and conductivity. […]

Thin quantum wires work better with less insulating coatings

Phys.org  May 4, 2022 Thin semiconducting wires, referred to as quantum wires, are often coated in insulating materials. Previous studies have explored how the mismatch between the insulating properties of both materials can influence their performance. Researchers in Vietnam have shown that thinner wires with less insulating coatings can improve the mobility of the electrons they carry. Previous models have presented conflicting conclusions about the ability of electrons to move through the wire, depending on whether coatings are more or less insulating than the semiconductor. The researchers considered the case where electrons are allowed to cross the outer boundary of […]

A simpler approach for creating quantum materials

Phys.org  May 4, 2022 Using twisted bilayer graphene to make devices remains challenging because of the low yield of fabricating twisted bilayer graphene. Researchers at the University of Pennsylvania have shown how patterned, periodic deformations of a single layer of graphene transforms it into a material with electronic properties previously seen in twisted graphene bilayers. To better understand the quantum geometrical properties of this system, they set out to understand the theory underlying how electrons move in this single-layered system. After running computer simulations of single-layered experiments, the researchers were surprised to find new evidence of unexpected phenomena along the […]

Zero-index metamaterials offer new insights into the foundations of quantum mechanics

Phys.org  April 27, 2022 Most theoretical derivations of fundamental radiative processes rely on energetic considerations and detailed balance equations, but not on momentum considerations. An international team of researchers (USA – Harvard University, University of Pennsylvania, Belgium, Spain, Denmark) re-examined the foundations of quantum physics from the perspective of momentum and explored what happens when the momentum of light is reduced to zero. They theoretically demonstrated that momentum recoil, transfer momentum from the field to the atom and Doppler shift are inhibited in NZI materials. Fundamental radiative processes inhibition is also explained due to those momentum considerations inside three-dimensional NZI […]

Top 10 Science and Technology Inventions for the Week of April 29, 2022

01. Breakthrough for efficient and high-speed spintronic devices 02. DARPA Seeks Ionospheric Insights to Improve Communication Across Domains 03. New hardware integrates mechanical devices into quantum tech 04. A novel insulating state emerges in a 2D material 05. Researchers create exotic magnetic structures with laser light 06. Researchers develop a paper-thin loudspeaker 07. Scientists turn a hydrogen molecule into a quantum sensor 08. Two teams use neutral atoms to create quantum circuits 09. Unexpected light behavior may be harnessed to improve optical communications and sensors 10. A new guide to extremely powerful light pulses And others… China detects first human […]

Breakthrough for efficient and high-speed spintronic devices

Science Daily  April 25, 2022 How the spin evolves in the nanoworld on extremely short time scales, in one millionth of one billionth of a second, has remained largely mysterious. An international team of researchers (Austria, Canada, Germany, Switzerland, France, China) used a tabletop ultrafast soft X-ray microscope based on a high-energy Ytterbium laser to spatio-temporally resolve the spin dynamics inside rare earth materials. They recorded a series of snapshot images of the nanoscale rare earth magnetic structures providing rich information on the magnetic properties that are as accurate as those obtained using large-scale X-ray facilities. According to the researchers […]

China detects first human case of H3N8 bird flu

MedXpress  April 27, 2022 H3N8 is known to have been circulating since 2002 after first emerging in North American waterfowl. It is known to infect horses, dogs, and seals, but has not previously been detected in humans. China’s National Health Commission on Tuesday said a four-year-old boy living in central Henan province tested positive for the strain after being hospitalized earlier this month with a fever and other symptoms. The boy was infected directly by birds and the strain was not found to have “the ability to effectively infect humans”, the commission said. The H5N1 and H7N9 strains of bird […]

Climate change triggering global collapse in insect numbers, stressed farmland shows 63% decline: New research

Phys.org  April 21, 2022 Although research has shown that biodiversity changes are driven primarily by land-use change and increasingly by climate change, the potential for interaction between these drivers and insect biodiversity on the global scale remains unclear. Researchers in the UK have shown that the interaction between indices of historical climate warming and intensive agricultural land use is associated with reductions of almost 50% in the abundance and 27% in the number of species within insect assemblages relative to those in less-disturbed habitats with lower rates of historical climate warming. These patterns are particularly evident in the tropical realm. […]