An active supermassive black hole is one of the greatest wonders in the cosmos.
A dense, invisible object that can be billions of times the mass of our Sun is surrounded by a vast, churning disk and torus of material, blazing with light as it swirls down onto the black hole center. But how big do these structures grow?
In a study published in Matter, researchers led by Prof. Yang Zhaorong and Prof. Hao Ning from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences found that the quasi-one-dimensional charge density wave (CDW) material cupric telluride (CuTe) provides a rare and promising platform for the study of multiple CDW orders and superconductivity under high pressure.
The interplay between superconductivity and CDW has always been one of the central issues in the research of condensed matter physics. While theory generally predicts that they compete with each other, superconductivity and CDW can manifest complex relationships under external stimuli in practical materials. Additionally, recent research in the superconducting cuprates and the Kagome CsV3Sb5 has found that superconductivity interacts with multiple CDW orders. However, in the above two systems, there are some other quantum orders in the phase diagrams, which hinders a good understanding of the interplay between superconductivity and multiple CDWs.
In this study, the researchers provided solid evidence for a second CDW order in the quasi-one-dimensional CDW material CuTe under high pressure. In addition, they found that superconductivity can be induced and that it has complex relationships with the native and emergent CDW orders.
To assist humans during their day-to-day activities and successfully complete domestic chores, robots should be able to effectively manipulate the objects we use every day, including utensils and cleaning equipment. Some objects, however, are difficult to grasp and handle for robotic hands, due to their shape, flexibility, or other characteristics.
These objects include textile-based cloths, which are commonly used by humans to clean surfaces, polish windows, glass or mirrors, and even mop the floors. These are all tasks that could be potentially completed by robots, yet before this can happen robots will need to be able to grab and manipulate cloths.
Continue reading “A technique to facilitate the robotic manipulation of crumpled cloths” »
Not all of the material around us is stable. Some materials may undergo radioactive decay to form more stable isotopes. Scientists have now observed a new decay mode for the first time. In this decay, a lighter form of oxygen, oxygen-13 (with eight protons and five neutrons), decays by breaking into three helium nuclei (an atom without the surrounding electrons), a proton, and a positron (the antimatter version of an electron).
Scientists observed this decay by watching a single nucleus break apart and measuring the breakup products. The study is published in the journal Physical Review Letters.
Scientists have previously observed interesting modes of radioactive decay following the process called beta-plus decay. This is where a proton turns into a neutron and emits some of the produced energy by emitting a positron and an antineutrino. After this initial beta-decay, the resulting nucleus can have enough energy to boil off extra particles and make itself more stable.
A study recently published in the journal Nanophotonics reveals that by rapidly modulating the refractive index – which is the ratio of the speed of electromagnetic radiation in a medium compared to its speed in a vacuum – it’s possible to produce photonic time crystals (PTCs) in the near-visible part of the spectrum.
The study’s authors suggest that the ability to sustain PTCs in the optical domain could have profound implications for the science of light, enabling truly disruptive applications in the future.
PTCs, materials in which the refractive index rises and falls rapidly in time, are the temporal equivalent of photonic crystals in which the refractive index oscillates periodically in space causing, for example, the iridescence of precious minerals and insect wings.
The prized materials could be transformative for research — but only if they have other essential qualities.
The system is like a solid version of pumped hydro, which uses surplus generating capacity to pump water uphill into a reservoir. When the water’s released it flows down through turbines, making them spin and generate energy.
Energy Vault’s solid gravity system uses huge, heavy blocks made of concrete and composite material and lifts them up in the air with a mechanical crane. The cranes are powered by excess energy from the grid, which might be created on very sunny or windy days when there’s not a lot of demand. The blocks are suspended at elevation until supply starts to fall short of demand, and when they’re lowered down their weight pulls cables that spin turbines and generate electricity.
Continue reading “Energy Vault’s First Grid-Scale Gravity Energy Storage System Is Near Complete” »
When two sheets of graphene are placed on top of each other and slightly twisted, their atoms form a moiré pattern, or superlattice. At the so-called “magic” twist angle of 1.08°, something unusual happens: the weak van der Waals (vdW) coupling between atoms in adjacent layers modifies the atoms’ electronic states and transforms the material from a semimetal to a superconductor. The study of such twist-related electronic effects is known as “twistronics”, and it also includes phenomena such as correlated insulator states that appear at different degrees of misalignment.
Because the moiré pattern that underlies twistronics appears only at the interface between two thin sheets, it was assumed that twistronic effects could only occur in structures containing just a few layers. Although it is possible to produce a moiré pattern at a two-dimensional interface within a three-dimensional structure, it was thought that this pattern would not substantially modify the properties of the bulk material. After all, the 2D moiré region would only comprise a small fraction of the total 3D crystal volume.
New work by two research groups – one at the University of Washington in the US and Osaka University in Japan, the other at the University of Manchester in the UK – shows that this picture is not always correct. In fact, rotating a single layer of a 2D material by a small twist angle within a three-dimensional graphite film can cause the properties of the moiré interface to become inextricably mixed with those of the graphite. The result is a new class of hybrid 2D-3D moiré materials that substantially alters our understanding of how twistronics works.
67 years after its theoretical prediction by David Pines, the elusive “demon” particle, a massless and neutral entity in solids, has been detected in strontium ruthenate, underscoring the value of innovative research approaches.
In 1956, theoretical physicist David Pines predicted that electrons in a solid can do something strange. Although electrons typically have a mass and an electric charge, Pines asserted that they could combine to create a composite particle that is massless, neutral, and doesn’t interact with light. He named this theoretical particle a “demon.” Since then, it has been theorized to play an important role in the behaviors of a wide variety of metals. Unfortunately, the same properties that make it interesting have allowed it to elude detection since its prediction.
Fast forward 67 years, and a research team led by Peter Abbamonte, a professor of physics at the University of Illinois Urbana-Champaign (UIUC), has finally found Pines’ elusive demon. As the researchers report in the journal Nature, they used a nonstandard experimental technique that directly excites a material’s electronic modes, allowing them to see the demon’s signature in the metal strontium ruthenate.
The Laser-Induced Breakdown Spectroscopy (LIBS) instrument onboard Chandrayaan-3 Rover has made the first-ever in-situ measurements on the elemental composition of the lunar surface near the south pole. These in-situ measurements confirm the presence of Sulphur (S) in the region unambiguously, something that was not feasible by the instruments onboard the orbiters.
LIBS is a scientific technique that analyzes the composition of materials by exposing them to intense laser pulses. A high-energy laser pulse is focused onto the surface of a material, such as a rock or soil. The laser pulse generates an extremely hot and localized plasma. The collected plasma light is spectrally resolved and detected by detectors such as Charge Coupled Devices. Since each element emits a characteristic set of wavelengths of light when it’s in a plasma state, the elemental composition of the material is determined.
Preliminary analyses, graphically represented, have unveiled the presence of Aluminum (Al), Sulphur (S), Calcium (Ca), Iron (Fe), Chromium (Cr), and Titanium (Ti) on the lunar surface. Further measurements have revealed the presence of manganese (Mn), silicon (Si), and oxygen (O). Thorough investigation regarding the presence of Hydrogen is underway.
