How did the Arava, a punishingly hot and arid desert, become one of Israel’s breadbaskets? It’s a story of determination and thinking outside the box.
The discovery could inform the design of practical superconducting devices. When it comes to graphene, it appears that superconductivity runs in the family. Graphene is a single-atom-thin 2D material that can be produced by exfoliation from the same graphite that is found in pencil lead. The u.
The discovery could inform the design of practical superconducting devices.
When it comes to graphene.
Graphene is an allotrope of carbon in the form of a single layer of atoms in a two-dimensional hexagonal lattice in which one atom forms each vertex. It is the basic structural element of other allotropes of carbon, including graphite, charcoal, carbon nanotubes, and fullerenes. In proportion to its thickness, it is about 100 times stronger than the strongest steel.
The sterile neutrino, if it truly exists, only answers to gravity.
Physicists are spelunking the complex findings from an experimental particle reactor found a mile below the surface in the mountains of Russia. What they found has the potential to send an earthquake through the bedrock of the standard model of physics itself: the results could confirm a new elementary particle, called a “sterile neutrino,” or demonstrate a need to revise a portion of the standard model.
The research comes from New Mexico’s Los Alamos National Laboratory in collaboration with the Baksan Neutrino Observatory near the Georgia border in far southwestern Russia. The scientists outlined their findings in two new papers published last month in the journals Physical Review Letters and Physical Review C.
To understand the team’s findings, we need to talk about neutrinos, the most common and least massive of the massive particles (the particles that have any mass at all). They were first theorized decades ago and only interact through gravity and the “weak force” of the standard model of physics, which means that, like dark matter, neutrinos can just pass through us and our planet and space however they want; they interact with almost nothing. Over the decades, scientists have developed ways to measure neutrinos by tracing their effect on what’s around them.
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When talking about quantum physics, people will often nonchalantly say that particles can be in two places at once. Physicist Sabine Hossenfelder explores what is actually going on.
Ten years ago this week, two international collaborations of groups of scientists, including a large contingent from Caltech, confirmed that they had found conclusive evidence for the Higgs boson, an elusive elementary particle, first predicted in a series of articles published in the mid-1960s, that is thought to endow elementary particles with mass.
Fifty years prior, as theoretical physicists endeavored to understand the so-called electroweak theory, which describes both electromagnetism and the weak nuclear force (involved in radioactive decay), it became apparent to Peter Higgs, working in the UK, and independently to François Englert and Robert Brout, in Belgium, as well as U.S. physicist Gerald Guralnik and others, that a previously unidentified field that filled the universe was required to explain the behavior of the elementary particles that compose matter. This field, the Higgs field, would lead to a particle with zero spin, significant mass, and have the ability to spontaneously break the symmetry of the earliest universe, allowing the universe to materialize. That particle became known as the Higgs boson.
Over the decades that followed, experimental physicists first devised and then developed the instruments and methods required to detect the Higgs boson. The most ambitious of these projects was the Large Hadron Collider (LHC), which is operated by the European Organization for Nuclear Research, or CERN. Since the planning of the LHC in the late 1980s, the U.S. Department of Energy and the National Science Foundation have worked in collaboration with CERN to provide funding and technology know-how, and to support thousands of scientists helping to search for the Higgs.
Scientists at Tokyo Institute of Technology designed a new type of molecular wire doped with organometallic ruthenium to achieve unprecedentedly higher conductance than earlier molecular wires. The origin of high conductance in these wires is fundamentally different from similar molecular devices and suggests a potential strategy for developing highly conducting “doped” molecular wires.
Since their conception, researchers have tried to shrink electronic devices to unprecedented sizes, even to the point of fabricating them from a few molecules. Molecular wires are among the building blocks of such minuscule contraptions, and many researchers have been developing strategies to synthesize highly conductive, stable wires from carefully designed molecules.
A team of researchers from Tokyo Institute of Technology, including Yuya Tanaka, designed a novel molecular wire in the form of a metal electrode-molecule-metal electrode (MMM) junction including a polyyne, an organic chain-like molecule, “doped” with a ruthenium-based unit Ru(dppe)2. The proposed design, featured in the cover of the Journal of the American Chemical Society, is based on engineering the energy levels of the conducting orbitals of the atoms of the wire, considering the characteristics of gold electrodes.
A major goal in the field of molecular electronics, which aims to use single molecules as electronic components, is to make a device where a quantized, controllable flow of charge can be achieved at room temperature. A first step in this field is for researchers to demonstrate that single molecules can function as reproducible circuit elements such as transistors or diodes that can easily operate at room temperature.
A team led by Latha Venkataraman, professor of applied physics and chemistry at Columbia Engineering and Xavier Roy, assistant professor of chemistry (Arts & Sciences), published a study in Nature Nanotechnology that is the first to reproducibly demonstrate current blockade—the ability to switch a device from the insulating to the conducting state where charge is added and removed one electron at a time—using atomically precise molecular clusters at room temperature.
Bonnie Choi, a graduate student in the Roy group and co-lead author of the work, created a single cluster of geometrically ordered atoms with an inorganic core made of just 14 atoms—resulting in a diameter of about 0.5 nanometers—and positioned linkers that wired the core to two gold electrodes, much as a resistor is soldered to two metal electrodes to form a macroscopic electrical circuit (e.g. the filament in a light bulb).
The ability to turn superconductivity off and on with a literal flip of a switch in so-called “magic-angle twisted graphene” has allowed engineers at Caltech to observe an unusual phenomenon that may shed new light on superconductivity in general.
The research, led by Stevan Nadj-Perge, assistant professor of applied physics and materials science, was published in the journal Nature on June 15.
Magic-angle twisted graphene, first discovered in 2018, is made from two or three sheets of graphene (a form of carbon consisting of a single layer of atoms in a honeycomb-like lattice pattern) layered atop one another, with each sheet twisted at precisely 1.05 degrees in relation to the one below it. The resulting bilayer or trilayer has unusual electronic properties: for example, it can be made into an insulator or a superconductor depending on how many electrons are added.
Martin ChartrandListen to the sound, more like a musket than a 3D printed plastic gun.
Second video shows the attempted assassination of former Japanese Prime Minister Shinzo Abe
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When it comes to graphene, it appears that superconductivity runs in the family.
Graphene is a single-atom-thin material that can be exfoliated from the same graphite that is found in pencil lead. The ultrathin material is made entirely from carbon atoms that are arranged in a simple hexagonal pattern, similar to that of chicken wire. Since its isolation in 2004, graphene has been found to embody numerous remarkable properties in its single-layer form.
In 2018, MIT researchers found that if two graphene layers are stacked at a very specific “magic” angle, the twisted bilayer structure could exhibit robust superconductivity, a widely sought material state in which an electrical current can flow through with zero energy loss. Recently, the same group found a similar superconductive state exists in twisted trilayer graphene—a structure made from three graphene layers stacked at a precise, new magic angle.
The LUX-ZEPLIN detector searched for elusive WIMP particles for 60 days on its first scientific run. Did it detect dark matter?
