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Category: particle physics – Page 444

Researchers at Empa and EPFL have created one of the smallest motors ever made. It’s composed of just 16 atoms, and at that tiny size it seems to function right on the boundary between classical physics and the spooky quantum realm.

Like its macroscopic counterparts, this mini motor is made up of a moving part (the rotor) and a fixed part (the stator). The stator in this case is a cluster of six palladium atoms and six gallium atoms arranged in a rough triangular shape. Meanwhile, the rotor is a four-atom acetylene molecule, which rotates on the surface of the stator. The whole machine measures less than a nanometer wide.

The molecular motor can be powered by either thermal or electrical energy, although the latter was found to be much more useful. At room temperature, for example, the rotor was found to rotate back and forth at random. But when an electric current was applied using an electron scanning microscope, the rotor would spin in one direction with a 99-percent stability.

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On September 10, 2008, CERN’s Large Hadron Collider (LHC) fired up for the very first time. In the decade since, the world’s largest and most powerful particle accelerator has been responsible for some of the most important breakthroughs in scientific history, most notably the discovery of the Higgs boson in 2013. New Atlas is celebrating the 10-year anniversary with a look back at the LHC’s achievements and, with a massive new upgrade in the works, what physics puzzles it could help piece together in the future.

Not only is the Large Hadron Collider the world’s largest particle accelerator, it’s the world’s largest machine, full-stop. That’s thanks to a 27-km-long (16.7-mi) ring of pipes that house the particle beams, along with thousands of powerful magnets and an advanced cooling system of liquid helium.

The ring is made up of two separate tubes, with high-energy particle beams circling in opposite directions. Superconducting electromagnets accelerate the particles almost to the speed of light, and for those to work they need to be kept extremely cold: −271.3° C (−456.3° F) to be exact, which is colder than outer space. That’s where the liquid helium comes in, chosen because it’s the only known element to remain in a liquid form at such low temperatures.

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A research team from Empa and EPFL has developed a molecular motor which consists of only 16 atoms and rotates reliably in one direction. It could allow energy harvesting at the atomic level. The special feature of the motor is that it moves exactly at the boundary between classical motion and quantum tunneling — and has revealed puzzling phenomena to researchers in the quantum realm.

The smallest motor in the world—consisting of just 16 atoms: this was developed by a team of researchers from Empa and EPFL. “This brings us close to the ultimate size limit for molecular motors,” explains Oliver Gröning, head of the Functional Surfaces Research Group at Empa. The motor measures less than one nanometer—in other words it is around 100,000 times smaller than the diameter of a human hair.

In principle, a molecular machine functions in a similar way to its counterpart in the macro world: it converts energy into a directed movement. Such molecular motors also exist in nature—for example in the form of myosins. Myosins are that play an important role in living organisms in the contraction of muscles and the transport of other molecules between cells.

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The cosmos contains a Higgs field—similar to an electric field—generated by Higgs bosons in the vacuum. Particles interact with the field to gain energy and, through Albert Einstein’s iconic equation, E=mc2, mass. The Standard Model of particle physics, although successful at describing elementary particles and their interactions at low energies, does not include a viable and hotly debated dark-matter particle. The only possible candidates, neutrinos, do not have the right properties to explain the observed dark matter.

“One particularly interesting possibility is that these long-lived dark particles are coupled to the Higgs boson in some fashion—that the Higgs is actually a portal to the dark world. We know for sure there’s a dark world, and there’s more energy in it than there is in ours. It’s possible that the Higgs could actually decay into these long-lived particles,” said LianTao Wang, a University of Chicago physicist, in 2019, referring to the last holdout particle in physicists’ grand theory of how the universe works, discovered at the LHC in 2012, filling the last gap in the standard model of fundamental particles and forces. Since then, the standard model has stood up to every test, yielding no hints of new physics.

The dark world makes up more than 95 percent of the universe, but scientists only know it exists from its effects—” like a poltergeist you can only see when it pushes something off a shelf.” We know there’s dark matter because like the poltergeist, we can see gravity acting on it keeping galaxies from flying apart.

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A similar glow is sometimes seen by astronauts on the space station when they look to the Earth’s limb.

The glow comes from oxygen atoms when they’re excited by sunlight.

The phenomenon has long been predicted to occur on other planets, but the Trace Gas Orbiter (TGO) — a joint European-Russian satellite at Mars — is the first to make the observation beyond Earth.

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The European Space Agency (ESA) has just announced that its ExoMars Trace Gas Orbiter (TGO) has identified a long-suspected “green glow” around Mars. The green glow is due to the interaction of sunlight with atoms and molecules in Mars’ atmosphere. To date, we’ve only observed the phenomenon around one other planet: Earth. Now, the scientists who’ve discovered the Red Planet’s green glow say it could help us better understand the planet’s atmosphere. And how to land safely on its surface.

An artist’s illustration of the green glow around Mars. ESA

Futurism reported on the finding, which was outlined in a paper recently published in the journal, Nature. According to the paper, this discovery marks the first time scientists have observed the “day glow” and “night glow” that generate the “green line” around Earth around Mars. Or any other planet. The discovery also stands as long sought-after confirmatory evidence of predictions regarding the Martian atmosphere, which date back 40 years.

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The world’s largest atom smasher has “given birth” to a set of four ultraheavy particles — called top quarks.

The formation of these chubby-but-tiny quadruplets, at the Large Hadron Collider in Geneva, Switzerland, has long been predicted by the Standard Model, the prevailing physics theory that governs subatomic interactions. But new physics theories suggest they could be created much more often than the Standard Model predicts. Finding more of such foursomes is the first step in testing those theories. The new findings were announced at the LHCP 2020 Conference.

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Circa 2019 o,.0.

How did the universe evolve from a point of singularity, known as the Big Bang, into a massive structure whose boundaries seem limitless? New clues and insight into the evolution of the universe have recently been provided by an international team of physicists, who performed the most detailed large-scale simulation of the universe to date.

The researchers made their own universe in a box — a cube of space spanning more than 230 million light-years across. Previous cosmological simulations were either very detailed but spanned a small volume or less detailed across large volumes. The new simulation, known as TNG50, managed to combine the best of two worlds, producing a large-scale replica of the cosmos while, at the same time, allowing for unprecedented computational resolution.

The level of detail is incredible, matching what was once only possible to do in simulations of individual galaxies. TNG50, in fact, tracks 20 billion particles representing dark matter, stars, cosmic gas, magnetic fields, and supermassive black holes.

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Laser-wakefield accelerators have led to the development of compact, ultrashort X-ray or gamma-ray sources to deliver peak brilliance, similar to conventional synchrotron sources. However, such sources are withheld by low efficiencies and limited to 107–8 photons per shot in the kiloelectron volt (KeV) to megaelectron volt (MeV) range. In a new report now published on Science Advances, Xing-Long Zhu and a research team in physics and astronomy in China and the U.K., presented a new approach to efficiently produce collimated, ultrabright gamma (γ)-ray beams. The resulting photon energies were tunable for up to gigaelectron volts by focussing a multi-petawatt laser pulse into a 2-stage wakefield accelerator. The high-intensity laser allowed them to efficiently generate a multi-gigaelectron volt electron beam with a high density and charge during the first stage of the experiment. The laser and electron beams entered a high-density plasma region in the second stage thereafter. Using numerical simulations, they demonstrated the production of more than 1012 gamma ray photons per shot with energy conversion efficiency above 10 percent for photons above 1 megaelectron volt (MeV) and achieved a peak brilliance above 1026 photons S-1 mm-2 mrad-2 per 0.1 percent bandwidth at 1 MeV. This research outcome will offer new avenues in both fundamental and applied physics and engineering.

Bright sources of high-energy gamma rays are versatile for broad areas of applications, including fundamental research in astrophysics, particle and nuclear physics, as well as high-resolution imaging. Researchers can improve such applications with compact gamma ray sources with low divergence, short pulse duration, high energy, and high peak brilliance. While widely used synchrotrons and X-ray free electron lasers (XFELS) can deliver X-ray pulses with peak brilliance, they are limited to low photon energies. The size and cost of such research structures can also limit their regular applications. Researchers have therefore rapidly developed compact laser-wakefield accelerators (LWFAs) in the past two decades to offer a radically different approach to drive the acceleration and radiation of high-energy particles on a much smaller scale. Continuous advancements in the field of ultrahigh-power laser technology will enable brilliant high-energy gamma sources.

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