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Category: particle physics – Page 532

Dark matter is an unknown type of matter present in the universe that could be of particle origin. One of the most complete theoretical frameworks that includes a dark matter candidate is supersymmetry. Many supersymmetric models predict the existence of a new stable, invisible particle called the lightest supersymmetric particle (LSP), which has the right properties to be a dark matter particle.

The ATLAS Collaboration at CERN has recently reported two new results on searches for an LSP that exploited the experiment’s full Run 2 data sample taken at 13 TeV proton-proton collision energy. The analyses looked for the pair production of two heavy supersymmetric particles, each of which decays to observable Standard Model particles and an LSP in the detector.

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The results are fascinating and spur the imagination, but don’t start investing in flux capacitors yet. This experiment also shows us that sending even a simulated particle back in time requires serious outside manipulation. To create such an external force to manipulate even one physical particle’s quantum waves is well beyond our abilities.

“We demonstrate that time-reversing even ONE quantum particle is an unsurmountable task for nature alone,” study author Vinokur wrote to the New York Times in an email [emphasis original]. “The system comprising two particles is even more irreversible, let alone the eggs — comprising billions of particles — we break to prepare an omelet.”

A press release from the Department of Energy notes that for the “timeline required for [an external force] to spontaneously appear and properly manipulate the quantum waves” to appear in nature and unscramble an egg “would extend longer than that of the universe itself.” In other words, this technology remains bound to quantum computation. Subatomic spas that literally turn back the clock aren’t happening.

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A team of researchers from the University of Central Florida and Michigan Technological University has developed a laser system concept built on the principles of supersymmetry. In their paper published in the journal Science, the group reports that their system is meant to solve the problem of producing more light with a compact laser system. Tsampikos Kottos with Wesleyan University has written a Perspective piece on the work done by the team in the same journal issue.

Kottos points out that there are a lot of physics applications that require use of a compact laser system that also has high-output power requirements. To fulfill this need, many physicists have taken to combining multiple lasers into an array. Unfortunately, this approach suffers from the production of a lesser-quality beam. Kottos notes that one way to overcome this problem is to use selective amplification of a single mode—but doing so has its own drawbacks. In this new effort, the researchers have come up with a different approach—one based on the principles of .

Supersymmetry is a math-based theory that describes the relationship between bosons and —it suggests that for every known elementary particle, there has to be a much heavier “super partner.” To build a new kind of laser system, the researchers used this idea to create a stable array of semiconductor lasers that together offer the power needed for prospective applications. More specifically, they designed a system that emphasizes the fundamental mode by suppressing higher-order modes. They did this by pairing them with low-quality modes—their lossy super-partners. The idea was for the to support them such that they were phase-matched with the higher order modes.

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Some of the most famous scientific discoveries happened by accident. From Teflon and the microwave oven to penicillin, scientists trying to solve a problem sometimes find unexpected things. This is exactly how we created phosphorene nanoribbons – a material made from one of the universe’s basic building blocks, but that has the potential to revolutionize a wide range of technologies.

We’d been trying to separate layers of phosphorus crystals into two-dimensional sheets. Instead, our technique created tiny, tagliatelle-like ribbons one single atom thick and only 100 or so atoms across, but up to 100,000 atoms long. We spent three years honing the production process, before announcing our findings.

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Majorana particles are very peculiar members of the family of elementary particles. First predicted in 1937 by the Italian physicist Ettore Majorana, these particles belong to the group of so-called fermions, a group that also includes electrons, neutrons and protons. Majorana fermions are electrically neutral and also their own anti-particles. These exotic particles can, for example, emerge as quasi-particles in topological superconductors and represent ideal building blocks for topological quantum computers.

Going to two dimensions

On the road to such topological quantum computers based on Majorana quasi-particles, physicists from the University of W\xFCrzburg together with colleagues from Harvard University (USA) have made an important step: Whereas previous experiments in this field have mostly focused on one-dimensional systems, the teams from W\xFCrzburg and Harvard have succeeded in going to two-dimensional systems.

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Nanostructures can be designed such a way that the quantum confinement allows only certain electron energy levels. Researchers from IMDEA Nanociencia, UAM and ICMM-CSIC have, for the first time, observed a discrete pattern of electron energies in an unconfined system, which could lead to new ways of modifying the surface properties of materials.

A research group from IMDEA Nanoscience and Universidad Autónoma de Madrid has found for the first time experimental evidence that one-dimensional lattices with nanoscale periodicity can interact with the electrons from a bidimensional gas by spatially separating their different wavelengths by means of a physical phenomenon known as Bragg diffraction. This phenomenon is well-known for wave propagation in general and is responsible for the iridescent color observed upon illumination of a CD surface. Due to the wave-particle duality proposed by De Broglie in 1924, electrons also present a wave-like behavior and, thus, diffraction phenomena. Actually, the observation that low-energy free electrons undergo diffraction processes upon interaction with well-ordered atomic lattices on solid surfaces was the first experimental confirmation of the wave-particle duality.

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Gazibegović, Ph.D. candidate in the group of prof. Erik Bakkers at the department of Applied Physics, developed a device made of ultrathin networks of nanowires in the shape of “hashtags.” This device allows pairs of Majorana particles to exchange position and keep track of the changes occurred, in a phenomenon known as “braiding.” This event is considered as a striking proof of the existence of Majorana particles, and it represents a crucial step towards their use as building blocks for the development of quantum computers. With two Nature publications in her pocket, Gazibegović is ready to defend her Ph.D. thesis on May 10.

In 1937, the Italian theoretical physicist Ettore Majorana hypothesized the existence of a unique particle that is its own antiparticle. This particle, also referred to as a “Majorana fermion,” can also exist as a “quasiparticle,” a collective phenomenon that behaves like an individual particle, as in waves forming on the water. The water itself stays in the same place, but the wave can “travel” on the surface, as if it were a single particle in movement. For many years, physicists have been trying to find the Majorana particle without success. Yet, in the last decade, scientists from Eindhoven University of Technology have taken great leap forwards in proving the existence of Majorana particles, also thanks to the research of Gazibegović and her collaborations with the University of Delft, Philips Research and the University of California – Santa Barbara.

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Developed by the U.S. Naval Research Laboratory Plasma Physics Division, in conjunction with the Spacecraft Engineering Department, the Space PlasmA Diagnostic suitE (SPADE) experiment launched from Kennedy Space Center in Florida to the International Space Station onboard the SpaceX Dragon resupply mission (CRS-17), May 4.

Integrated onto the Space Test Program-Houston 6 (STP-H6) pallet, SPADE is designed to monitor background plasma conditions on-orbit the International Space Station and provide early warning of the onset of hazardous levels of charging.

The space environment is filled with a collection of electrically charged particles, plasma, and properties that depend on variable solar conditions. Satellite operations in space require continuous monitored plasma conditions and the results it has on spacecraft.

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