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Category: particle physics – Page 576

Experiments at PPPL show remarkable agreement with satellite sightings

As on Earth, so in space. A four-satellite mission that is studying magnetic reconnection—the breaking apart and explosive reconnection of the magnetic field lines in plasma that occurs throughout the universe—has found key aspects of the process in space to be strikingly similar to those found in experiments at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL). The similarities show how the studies complement each other: The laboratory captures important global features of reconnection and the spacecraft documents local key properties as they occur.

The observations made by the Magnetospheric Multiscale Satellite (MMS) mission, which NASA launched in 2015 to study in the magnetic field that surrounds the Earth, correspond quite well with past and present laboratory findings of the Magnetic Reconnection Experiment (MRX) at PPPL. Previous MRX research uncovered the process by which rapid reconnection occurs and identified the amount of magnetic that is converted to particle energy during the process, which gives rise to northern lights, and geomagnetic storms that can disrupt cell phone service, black out power grids and damage orbiting satellites.

Harnessing the power of ‘spin orbit’ coupling in silicon: Scaling up quantum computation

Australian scientists have investigated new directions to scale up qubits—utilising the spin-orbit coupling of atom qubits—adding a new suite of tools to the armory.

Spin-orbit coupling, the coupling of the qubits’ orbital and spin degree of freedom, allows the manipulation of the via electric, rather than magnetic-fields. Using the electric dipole coupling between qubits means they can be placed further apart, thereby providing flexibility in the chip fabrication process.

In one of these approaches, published in Science Advances, a team of scientists led by UNSW Professor Sven Rogge investigated the spin-orbit coupling of a boron atom in silicon.

Henri Becquerel and the Serendipitous Discovery of Radioactivity

Antoine Henri Becquerel (born December 15, 1852 in Paris, France), known as Henri Becquerel, was a French physicist who discovered radioactivity, a process in which an atomic nucleus emits particles because it is unstable. He won the 1903 Nobel Prize in Physics with Pierre and Marie Curie, the latter of whom was Becquerel’s graduate student. The SI unit for radioactivity called the becquerel (or Bq), which measures the amount of ionizing radiation that is released when an atom experiences radioactive decay, is also named after Becquerel.

Becquerel was born December 15, 1852 in Paris, France, to Alexandre-Edmond Becquerel and Aurelie Quenard. At an early age, Becquerel attended the preparatory school Lycée Louis-le-Grand, located in Paris. In 1872, Becquerel began attending the École Polytechnique and in 1874 the École des Ponts et Chaussées (Bridges and Highways School), where he studied civil engineering.

New Research Could Rewrite Physics From the Ground Up

Four researchers came together to propose the addition of six novel particles to tackle five enduring issues within the current Standard Model Theory. This new proposed model, detailed in APS Physics, is named SMASH for “Standard Model Axion See-saw Higgs portal inflation.” The team proposed that particles rho and axion could explain inflation and dark matter respectively, along with three heavy right-handed neutrinos.

With these findings, the researchers hope to answer the following questions about the Standard Model:

Researchers Just Created a New Form of Matter

There’s a new form of matter out there and it’s called a supersolid. Born in the labs of researchers from the Massachusetts Institute of Technology (MIT), this new matter is seemingly a contradiction. The supersolid combines properties of solids and superfluids — or fluids with zero viscosity, thereby flowing without losing kinetic energy. Supersolids have previously been predicted by physicists, but have not been observed in a lab until now.

“It is counterintuitive to have a material which combines superfluidity and solidity,” says team leader Wolfgang Ketterle, the John D. MacArthur Professor of Physics at MIT and 2001 Noble laureate. “If your coffee was superfluid and you stirred it, it would continue to spin around forever.” Their research was published in the journal Nature.

To develop this seemingly contradictory form of matter, Ketterle’s team manipulated the motion of atoms in a superfluid state of dilute gas, called a Bose-Einstein condensate, or BEC. Ketterle co-discovered BEC, which won him his Noble prize in physics. “The challenge was now to add something to the BEC to make sure it developed a shape or form beyond the shape of the ‘atom trap,’ which is the defining characteristic of a solid,” Ketterle explained.

Physicists finally calculated where the proton’s mass comes from

A proton’s mass is more than just the sum of its parts. And now scientists know just what accounts for the subatomic particle’s heft.

Protons are made up of even smaller particles called quarks, so you might expect that simply adding up the quarks’ masses should give you the proton’s mass. However, that sum is much too small to explain the proton’s bulk. And new, detailed calculations show that only 9 percent of the proton’s heft comes from the mass of constituent quarks. The rest of the proton’s mass comes from complicated effects occurring inside the particle, researchers report in the Nov. 23 Physical Review Letters.

Quarks get their masses from a process connected to the Higgs boson, an elementary particle first detected in 2012 (SN: 7/28/12, p. 5). But “the quark masses are tiny,” says study coauthor and theoretical physicist Keh-Fei Liu of the University of Kentucky in Lexington. So, for protons, the Higgs explanation falls short.

MIT Studies Micro-Impacts at 100 Million Frames Per Second

Engineers know that tiny, super-fast objects can cause damage to spacecraft, but it’s been difficult to understand exactly how the damage happens because the moment of impact is incredibly brief. A new study from MIT seeks to reveal the processes at work that produce microscopic craters and holes in materials. The hope is that by understanding how the impacts work, we might be able to more durable materials.

Accidental space impacts aren’t the only place these mechanisms come into play. There are also industrial applications on Earth like applying coatings, strengthening metallic surfaces, and cutting materials. A better understanding of micro-impacts could also make these processes more efficient. Observing such impacts was not easy, though.

For the experiments, the MIT team used tin particles about 10 micrometers in diameter accelerated to 1 kilometer per second. They used a laser system to launch the projectile that instantly evaporates a surface material and ejects the particles, ensuring consistent timing. That’s important because the high-speed camera pointed at the test surface (also tin) needed specific lighting conditions. At the appointed time, a second laser illuminated the particle allowing the camera to follow the impact at up to 100 million frames per second.

Ultracold quantum mix

The experimental investigation of ultracold quantum matter makes it possible to study quantum mechanical phenomena that are otherwise inaccessible. A team led by the Innsbruck physicist Francesca Ferlaino has now mixed quantum gases of two strongly magnetic elements, erbium and dysprosium, and created a dipolar quantum mixture.

A few years ago, it seemed unfeasible to extend the techniques of atom manipulation and deep cooling in the ultracold regime to many-valence-electron atomic species. The reason is the increasing complexity in the atomic spectrum and the unknown scattering properties. However, a team of researchers, led by Ben Lev at Stanford University and an Austrian team directed by Francesca Ferlaino at the University of Innsbruck demonstrated degeneracy of rare-earth species. Ferlaino’s group focused the on and developed a powerful, yet surprisingly simple approach to produce a Bose-Einstein condensate.

“We have shown how the complexity of atomic physics can open up new possibilities,” says Ferlaino. Magnetic species are an ideal platform to create dipolar quantum matter, in which particles interact with each other via a long-range and orientation dependent interaction as little quantum magnets.