Scientists around the world are testing ways to further boost the power of particle accelerators while drastically shrinking their size.
10/18/18
Our best model of particle physics explains only about 5 percent of the universe.
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Circa 2016
Entanglement is an extremely strong correlation that can exist between quantum systems. These correlations are so strong that two or more entangled particles have to be described with reference to each other, even though the individual objects may be spatially separated.
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Not everything about glass is clear. How its atoms are arranged and behave, in particular, is startlingly opaque.
The problem is that glass is an amorphous solid, a class of materials that lies in the mysterious realm between solid and liquid. Glassy materials also include polymers, or commonly used plastics. While it might appear to be stable and static, glass’ atoms are constantly shuffling in a frustratingly futile search for equilibrium. This shifty behavior has made the physics of glass nearly impossible for researchers to pin down.
Now a multi-institutional team including Northwestern University, North Dakota State University and the National Institute of Standards and Technology (NIST) has designed an algorithm with the goal of giving polymeric glasses a little more clarity. The algorithm makes it possible for researchers to create coarse-grained models to design materials with dynamic properties and predict their continually changing behaviors. Called the “energy renormalization algorithm,” it is the first to accurately predict glass’ mechanical behavior at different temperatures and could result in the fast discovery of new materials, designed with optimal properties.
For the first time, physicists at the University of Basel have succeeded in measuring the magnetic properties of atomically thin van der Waals materials on the nanoscale. They used diamond quantum sensors to determine the strength of the magnetization of individual atomic layers of the material chromium triiodide. In addition, they found a long-sought explanation for the unusual magnetic properties of the material. The journal Science has published the findings.
The use of atomically thin, two-dimensional van der Waals materials promises innovations in numerous fields in science and technology. Scientists around the world are constantly exploring new ways to stack different single atomic layers and thus engineer new materials with unique, emerging properties.
These super-thin composite materials are held together by van der Waals forces and often behave differently to bulk crystals of the same material. Atomically thin van der Waals materials include insulators, semiconductors, superconductors and a few materials with magnetic properties. Their use in spintronics or ultra-compact magnetic memory media is highly promising.
From the point of view of nuclear theory, the decay rates of both two-neutrino and neutrinoless double electron capture can be connected to quantities called nuclear matrix elements. Such quantities contain information about nuclear structure that is extracted from nuclear models and can be applied by researchers in the field of nuclear-structure theory.
For half a century, our view of the world has been based on the standard model of particle physics. However, this view has been challenged by theories that can overcome some of the limitations of the standard model. These theories allow neutrinos to be Majorana particles (that is, they are indistinguishable from their own antiparticles) and predict the existence of weakly interacting massive particles (WIMPs) as the constituents of invisible ‘dark matter’ in the Universe. Majorana neutrinos mediate a type of nuclear decay called neutrinoless double-β decay, an example of which is neutrinoless double electron capture. A crucial step towards observing this decay is to detect its standard-model equivalent: two-neutrino double electron capture. In a paper in Nature, the XENON Collaboration reports the first direct observation of this process in xenon-124 nuclei, using a detector that was built to detect WIMPs.
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Deep inside a mountain in central Italy, scientists are laying a trap for dark matter. The bait? A big metal tank full of 3.5 tons (3,200 kilograms) of pure liquid xenon. This noble gas is one of the cleanest, most radiation-proof substances on Earth, making it an ideal target for capturing some of the rarest particle interactions in the universe.
It all sounds vaguely sinister; said Christian Wittweg, a doctoral candidate at the University of Münster in Germany, who has worked with the so-called Xenon collaboration for half a decade, going to work every day feels like “paying a Bond villain a visit.” So far, the mountain-dwelling researchers haven’t captured any dark matter. But they recently succeeded in detecting one of the rarest particle interactions in the universe. [11 Biggest Unanswered Questions About Dark Matter]
According to a new study published today (April 24) in the journal Nature, the team of more than 100 researchers measured, for the first time ever, the decay of a xenon-124 atom into a tellurium 124 atom through an extremely rare process called two-neutrino double electron capture. This type of radioactive decay occurs when an atom’s nucleus absorbs two electrons from its outer electron shell simultaneously, thereby releasing a double dose of the ghostly particles called neutrinos.
Continue reading “Researchers Just Measured an Atom with a Half-Life of 18 Sextillion Years” »
Particles travelling through empty space can emit bright flashes of gamma rays by interacting with the quantum vacuum, according to a new study by researchers at the University of Strathclyde.
It has long been known that charged particles, such as electrons and protons, produce the electromagnetic equivalent of a sonic boom when their speeds exceed that of photons in the surrounding medium. This effect, known as Cherenkov emission, is responsible for the characteristic blue glow from water in a nuclear reactor, and is used to detect particles at the CERN Large Hadron Collider.
According to Einstein, nothing can travel faster than light in vacuum. Because of this, it is usually assumed that the Cherenkov emission cannot occur in vacuum. But according to quantum theory, the vacuum itself is packed full of “virtual particles”, which move momentarily in and out of existence.
Continue reading “Extracting something from nothing: A bright glow from empty space” »
