Phys.org July 13, 2023 Microwave absorption in radar stealth technology is faced with challenges in terms of its effectiveness in low-frequency regions. An international team of researchers (UK, Singapore) has developed a new laser-based method for producing an ultrawideband metamaterial-based microwave absorber with a highly uniform sheet resistance and negative magnetic permeability at resonant frequencies, which results in a wide bandwidth in the L- to S-band. The electrical sheet resistance uniformity was achieved with less than 5% deviation resulting in a microwave absorption coefficient between 97.2% and 97.7% within a 1.56–18.3 GHz bandwidth for incident angles of 0°–40°, and there […]
Shrinking light: Waveguiding scheme enables highly confined subnanometer optical fields
Phys.org July 17, 2023 Researchers in China developed an optical waveguide scheme to generate a sub-nanometer-confined optical field in a nano slit waveguiding mode in a coupled nanowire pair (CNP). They showed that, when a conventional waveguide mode with a proper polarization was evanescently coupled into a properly designed CNP with a central nano slit, it could be channeled into a high-purity nano slit mode within a waveguiding length <10 μm. The CNP could be either freestanding or on-chip by using a tapered fiber or planar waveguide for input-coupling, with a coupling efficiency up to 95%. Within the slit region, […]
Study offers a broader approach to quantum walks
Phys.org July 14, 2023 Quantum walks have been widely studied for their ability to simulate a wide range of transport phenomena. Physicists have previously studied two distinct types of quantum walk, but so far, they haven’t widely considered how their mathematical descriptions could be linked. They have long been considered the discrete-time and discrete space analogue of the Dirac equation and have been used as a primitive to simulate quantum field theories precisely because of some of their internal symmetries. Researchers in France have introduced a new family of quantum walks, a more general family named “twisted” quantum walkers, named […]
Thanks to trapped electrons, a material expected to be a conducting metal remains an insulator
Nanowerk July 13, 2023 Doped antiferromagnets host a vast array of physical properties and learning how to control them is one of the biggest challenges of condensed matter physics. La1.67Sr0.33NiO4 (LSNO) is a classic example of such a material. At low temperatures holes introduced via substitution of La by Sr segregate into lines to form boundaries between magnetically ordered domains in the form of stripes. The stripes become dynamic at high temperatures, but LSNO remains insulating presumably because an interplay between magnetic correlations and electron–phonon coupling localizes charge carriers. Magnetic degrees of freedom have been extensively investigated in this system, […]
Training robots how to learn, make decisions on the fly
Science Daily July 11, 2023 Autonomous lander missions on extraterrestrial bodies will need to sample granular material while coping with domain shift, no matter how well a sampling strategy is tuned on Earth. Researchers at the University of Illinois proposed an adaptive scooping strategy that uses deep Gaussian process method trained with meta-learning to learn on-line from very limited experience on the target terrains. Deep Meta-Learning with Controlled Deployment Gaps (CoDeGa) explicitly trained the deep kernel to predict scooping volume robustly under large domain shifts. Employed in a Bayesian Optimization sequential decision-making framework, the proposed method allowed the robot to […]
Top 10 Science and Technology Inventions for the Week of July 14, 2023
01. How splitting sound might lead to a new kind of quantum computer 02. Navigating the future of underwater geolocalization: How polarization patterns enable new technology 03. New material shows promise for next-generation memory technology 04. Organic electronics: Sustainability during the entire lifecycle 05. Researchers: We’ve Underestimated The Risk of Simultaneous Crop Failures Worldwide 06. Researchers devise new quantum photonics technique to create better holograms 07. Satellite security lags decades behind the state of the art 08. Scientists develop 2D nanosheets for sustainable carbon capture 09. Superconducting qubit foundry accelerates progress in quantum research 10. Unraveling the hidden growth of […]
A better understanding of turbulence
Science Daily July 11, 2023 The effect of turbulence is one of the largest uncertainty factors in modern climate models and weather forecasting. In turbulent flows, kinetic energy is transferred from large spatial scales to small ones, where it is converted to heat by viscosity. For strong turbulence Kolmogorov conjectured in 1941 that this energy transfer is dominated by inertial forces at intermediate spatial scales. Since Kolmogorov’s conjecture, the velocity difference statistics in this so-called inertial range have been expected to follow universal power laws for which theoretical predictions have been refined over the years. An international team of researchers […]
Blind spots in biodefense
Science February 16, 2023 According to a team of researchers in the US (Harvard University, New York University) more zoonotic diseases originated in the United States than in any other country during the second half of the 20th century. Of the many agencies that govern food animal production, the US Department of Agriculture is the most important, but even it has no authority to regulate on-farm animal production. Each year, the US consumes an estimated 1 billion pounds of “game” . Yet, most hunter-harvested meat is not inspected, and no sanitary measures are required. The US is the largest importer […]
How splitting sound might lead to a new kind of quantum computer
Phys.org July 5, 2023 Linear optical quantum computing provides a desirable approach to quantum computing, with only a short list of required computational elements. The similarity between photons and phonons points to the interesting potential for linear mechanical quantum computing using phonons in place of photons. Although single-phonon sources and detectors have been demonstrated, a phononic beam splitter element remains an outstanding requirement. Researchers at the University of Chicago demonstrated such an element, using two superconducting qubits to fully characterize a beam splitter with single phonons. They used the beam splitter to demonstrate two-phonon interference, a requirement for two-qubit gates […]
Navigating the future of underwater geolocalization: How polarization patterns enable new technology
Science Daily July 10, 2023 Current methods for underwater geolocalization rely on tethered systems with limited coverage or daytime imagery data in clear waters, leaving much of the underwater environment unexplored. Geolocalization in turbid waters or at night has been considered unfeasible due to absence of identifiable landmarks. Researchers at the University of Illinois, Urbana) have developed a novel method for underwater geolocalization using deep neural networks trained on ∼10 million polarization-sensitive images acquired globally, along with camera position sensor data. They achieved longitudinal accuracy of ∼55 km (∼1000 km) during daytime (nighttime) at depths up to ∼8 m, regardless […]