Lifeboat Foundation

Reflections from Brookhaven Lab physicists on culmination of 2020–22 U.S. high-energy physics community planning process.

A novel method for measuring nanoparticle size could have applications in industry and basic materials science research.

Nanoparticles are present in everything from paints to pharmaceutical products. While nanoparticles have many important characteristics, such as molecular composition and shape, it is their size that determines many chemical and physical properties. A new technique relying on an optical vortex—a laser beam whose wave fronts twist around a dark central region—allows researchers to characterize nanoparticle size rapidly and continuously [1]. This light-based size probe might one day find applications in numerous industrial settings and aid fundamental materials science research.

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Protons, once thought to be fundamental particles, have been known since 1968 to instead be composed of quarks. Some quarks are actually heavier than protons, but this wasn’t considered a problem because protons were thought to be made up purely of light quarks – two up and one down quark to be precise. However, new research shows protons also contain charm quarks, which are indeed heavier than protons, like a pot holding a bigger pot inside it.

“That goes against all common sense,” said Dr Juan Rojo of Vrije Universiteit Amsterdam in a statement. “It’s like buying a one-kilogram pack of salt, which then comes out two kilograms of sand.”

However, anyone highly attached to common sense dropped out of quantum mechanics courses in the first six weeks, so Rojo and co-authors were undeterred. In Nature they have revealed that less than one percent of the proton’s mass comes from quarks heavier than the proton.

Newly discovered magnetic interactions in the Kagome layered topological magnet TbMn₆Sn₆ could be the key to customizing how electrons flow through these materials. Scientists from the U.S. Department of Energy’s Ames National Laboratory and Oak Ridge National Laboratory conducted an in-depth investigation of TbMn₆Sn₆ to better understand the material and its magnetic characteristics. These results could impact future technology advancements in fields such as quantum computing, magnetic storage media, and high-precision sensors.

Kagomes are a type of material whose structure is named after a traditional Japanese basket weaving technique. The weave produces a pattern of hexagons surrounded by triangles and vice-versa. The arrangement of the atoms in Kagome metals reproduces the weaving pattern. This characteristic causes electrons within the material to behave in unique ways.

Solid materials have electronic properties controlled by the characteristics of their electronic band structure. The band structure is strongly dependent on the geometry of the atomic lattice, and sometimes bands may display special shapes such as cones. These special shapes, called topological features, are responsible for the unique ways electrons behave in these materials. The Kagome structure in particular leads to complex and potentially tunable features in the electronic bands.

A team of researchers with The NNPDF Collaboration has found new evidence to support the theory of “intrinsic” charm quarks. In their paper published in the journal Nature, the group describes how they used a machine learning model to develop a proton structure and then used it to compare against results from real-world collisions in particle accelerators and what they learned by doing so. Ramona Vogt, with Lawrence Livermore National Laboratory has published a News & Views piece in the same journal issue outlining the work by the team on this new effort. Nature has also published a podcast where Nick Petrić Howe and Benjamin Thompson discuss the work done by the team.

Prior research involving the use of particle accelerators has suggested that protons contain quarks that are held together by gluons. A reasonable amount of evidence has also shown that there are at least two up quarks and one down quark. There have also been theories suggesting that there is another, the so-called charm quark, but little real evidence of them exists. That might be changing, however, as the researchers on this new effort have used a new approach to “prove” that they exist.

They have found evidence of one small part (0.5%) of a proton’s momentum coming from a charm quark. The researchers found this new evidence by using a machine learning model to build a hypothetical proton structure, including different flavors of quarks, and of course the elusive charm quark. They then ran their model and compared characteristics of the model with real-world data that has been observed from over 500,000 collisions in accelerators over the last decade.

By epitaxially growing films from colloids, researchers show that they can monitor interactions and behaviors of the particles that are difficult—and sometimes impossible—to capture for similar films grown from atoms.

For general readers:

Is it possible that the particle physicists hard at work near Geneva, Switzerland, at the laboratory known as CERN that hosts the Large Hadron Collider, have opened a doorway or a tunnel, to, say, another dimension? Could they be accessing a far-off planet orbiting two stars in a distant galaxy populated by Jedi knights? Perhaps they have opened the doors of Europe to a fiery domain full of demons, or worse still, to central Texas in summer?

Mortals and Portals.

Researchers at the National Institute of Standards and Technology (NIST) have adapted their atom-based radio receiver to detect and display live color television and video games.

Atom-based communications systems are of practical interest because they could be physically smaller and more tolerant of noisy environments than conventional electronics. Adding video capability could enhance radio systems in, for example, remote locations or emergency situations.

NIST’s receiver uses atoms prepared in high-energy “Rydberg” states, which are unusually sensitive to electromagnetic fields, including radio signals. These sensors also enable signal power measurements linked to the international system of units (SI). The latest work, described in AVS Quantum Science, is the first to demonstrate video reception.

Faster computers, tap-proof communication, better car sensors—quantum technologies have the potential to revolutionize our lives just as the invention of computers or the internet once did. Experts worldwide are trying to implement findings from basic research into quantum technologies. To this end, they often require individual particles, such as photons—the elementary particles of light—with tailored properties.

However, obtaining individual particles is complicated and requires intricate methods. In a study recently published in the journal Science, researchers now present a new method that simultaneously generates two individual particles in form of a pair.