Phys.org August 9, 2023 The mechanical displacements in piezoelectric materials carry along macroscopic electric fields, allowing tunneling of acoustic waves across a vacuum gap beyond the charge-charge interaction distance. However, no rigorous proof of complete acoustic wave tunneling has been presented, and the conditions to achieve complete tunneling have not been identified. Researchers in Finland demonstrated analytically the condition for such phenomenon for arbitrary anisotropic crystal symmetries and orientations, and that complete transmission of the incoming wave occurred at the excitation frequency of leaky surface waves. They also showed that the complete transmission condition could be related to the surface […]
Physicists open new path to an exotic form of superconductivity
Phys.org August 8, 2023 Understanding the interplay of band topology and electronic interactions in topological systems remains a frontier question. A team of researchers in the US (Emory University, Stanford University) predicted new interacting electronic orders emerging near higher order Van Hove singularities present in the Chern bands of the Haldane model. They classified the nature of such singularities and employed unbiased renormalization group methods that unveiled a complex landscape of electronic orders, which included ferromagnetism, density waves, and superconductivity. Importantly, they showed that repulsive interactions could stabilize the long-sought pair-density-wave state and an exotic Chern supermetal, which is a […]
Quantum material exhibits ‘non-local’ behavior that mimics brain function
Phys.org August 8, 2023 A key aspect of how the brain learns and enables decision-making processes is through synaptic interactions. Electrical transmission and communication in a network of synapses are modulated by extracellular fields generated by ionic chemical gradients. Emulating such spatial interactions in synthetic networks can be of potential use for neuromorphic learning and the hardware implementation of artificial intelligence. A team of researchers in the US (Rutgers University, UC San Diego, Purdue University, Brookhaven National Laboratory, Argonne National Laboratory) has demonstrated that in a network of hydrogen-doped perovskite nickelate devices, electric bias across a single junction can tune […]
Scientists create novel approach to control energy waves in 4D
Science Daily July 31, 2023 Topological pumping allows waves to navigate a sample undisturbed by disorders and defects. An international team of researchers (USA – University of Missouri, China) demonstrated this phenomenon with elastic surface waves by strategically patterning an elastic surface to create a synthetic dimension. The surface was decorated with arrays of resonating pillars that were connected by spatially slow-varying coupling bridges and support eigenmodes located below the sound cone. They established a connection between the collective dynamics of the pillars and that of electrons in a magnetic field by developing a tight-binding model and a WKB (Wentzel-Kramers-Brillouin) […]
Super Radar: Breakthrough radar research overcomes a nearly century-old trade-off between wavelength and distance resolution
Science Daily August 2, 2023 An international team of researchers (Israel, USA – University of Rochester, Canada) studied the fundamental underpinnings of range resolution in coherent remote sensing. They used a novel class of self-referential interference functions to show that they could greatly improve upon currently accepted bounds for range resolution. They considered the range resolution problem from the perspective of single-parameter estimation of amplitude versus the traditional temporally resolved paradigm. They defined the minimum resolvable distance between two depths and the depth resolution between the objects as two figures of merit. They experimentally demonstrated that their system could resolve […]
Thermal imaging innovation allows AI to see through pitch darkness like broad daylight
Phys.org August 1, 2023 Traditional active sensors like LiDAR have drawbacks that increase as they are scaled up, including signal interference and risks to people’s eye safety. A team of researchers in the US (Purdue University, Michigan State University) proposed and experimentally demonstrated heat-assisted detection and ranging (HADAR) overcoming the open challenge of ghosting and benchmark it against AI-enhanced thermal sensing. HADAR not only sees texture and depth through the darkness as if it were day but also perceives decluttered physical attributes beyond RGB or thermal vision, paving the way to fully passive and physics-aware machine perception. They developed HADAR […]
The ‘unknome’: A database of human genes we know almost nothing about
Phys.org August 8, 2023 The human genome encodes approximately 20,000 proteins, many still uncharacterized. It has become clear that scientific research tends to focus on well-studied proteins, leading to a concern that poorly understood genes are unjustifiably neglected. To address this, researchers in the UK have developed a publicly available and customizable “Unknome database” that ranks proteins based on how little is known about them. They applied RNA interference (RNAi) in Drosophila to 260 unknown genes that are conserved between flies and humans. Knockdown of some genes resulted in loss of viability, and functional screening of the rest revealed hits […]
Top 10 Science and Technology Inventions for the Week of August 4, 2023
01. MIT engineers create an energy-storing supercapacitor from ancient materials 02. Bacteria as blacksmiths – new method to assemble unconventional materials 03. Can rainbows monitor the environment? 04. Enhanced light absorption in thin silicon photodetectors with photon-trapping structures 05. Extraordinarily strong, lightweight material combines DNA and glass 06. ‘Quantum avalanche’ explains how nonconductors turn into conductors 07. ‘Stunning’ discovery: Metals can heal themselves 08. Team creates simple superconducting device that could dramatically cut energy use in computing 09. Turning bacteria into solar factories with semiconductor nanoclusters 10. Some alloys don’t change size when heated, and we now know why And […]
Bacteria as blacksmiths – new method to assemble unconventional materials
Nanowerk July 27, 2023 When in equilibrium, thermal forces agitate molecules, which then diffuse, collide, and bind to form materials. However, the space of accessible structures in which micron-scale particles can be organized by thermal forces is limited, owing to the slow dynamics and metastable states. Active agents in a passive fluid generate forces and flows, forming a bath with active fluctuations. Two unanswered questions are whether those active agents can drive the assembly of passive components into unconventional states and which material properties they will exhibit. Researchers in Austria showed that passive, sticky beads immersed in a bath of […]
Can rainbows monitor the environment?
Nanowerk July 31, 2023 Surface enhanced Raman scattering (SERS) is becoming a highly topical technique for identifying and fingerprinting molecules. Crucial for SERS is the need for substrates with strong and reproducible enhancements of the Raman signal over large areas and with a low fabrication cost. An international team of researchers (UK, Germany, the Netherlands, Belgium) found that dense arrays of plasmonic nanohelices have excellent SERS properties. As an illustration, they presented two new ways to probe near-field enhancement generated with circular polarization at chiral metasurfaces, first using the Raman spectra of achiral molecules (crystal violet) and second using a […]