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Magnetic skyrmions have received much attention as promising, topologically protected quasiparticles with applications in spintronics. Skyrmions are small, swirling topological magnetic excitations with particle-like properties. Nevertheless, the lower stability of magnetic skyrmions only allow them to exist in a narrow temperature range, with low density of the particles, thus implying the need for an external magnetic field, which greatly limits their wider applications.

In a new report published in Science Advances, Yuzhu Song and a team of researchers formed high-density, spontaneous magnetic biskyrmions without a magnetic field in ferrimagnets via the thermal expansion of the lattice.

The team noted a strong connection between the atomic-scale ferrimagnetic structure and nanoscale magnetic domains in a ferrimagnet compound by using neutron powder diffraction and Lorentz transmission electron microscopy measurements.

New advances were made from LHC Run 2 data obtained between 2015 and 2018 but the scientists are yet to spot the monopoles.

Researchers at the European Council for Nuclear Research (CERN) are among those physicists who have been looking for magnetic monopoles. A recently published paper from the ATLAS Collaboration at CERN has confirmed that it continues to look for the elusive particle, a press release said.

The ATLAS Collaboration is one of science’s most significant collaborative efforts. Its webpage states that it consists of 0 members and 3,000 scientific authors comprised of physicists, engineers, technicians, students, and support staff from around the world.

While it has long been known that ultraviolet (UV) light can help kill disease-causing pathogens, the COVID-19 pandemic has put a spotlight on how these technologies can rid environments of germs. However, the excimer lamps and LEDs that can directly emit light in the required deep-UV wavelengths generally have low efficiency or suffer from short lifetimes. Moreover, UV light of the wrong wavelength can actually be harmful to human cells.

Now, a team led by researchers from Osaka University has shown how an optical device made of aluminum nitride can be used to generate deep-UV light in a method wholly different from previous approaches. The team made use of a process called “second harmonic generation,” which relies on the fact that the frequency of a photon, or particle of light, is proportional to its energy. The study is published in the journal Applied Physics Express.

Most transparent materials are considered “linear” with respect to their response to light, i.e., photons cannot interact with each other. However, inside certain “nonlinear” materials, two photons can be combined into a single photon with twice the energy, and thus, twice the frequency.

Magnets, those everyday objects we stick to our fridges, all share a unique characteristic: they always have both a north and a south pole. Even if you tried breaking a magnet in half, the poles would not separate—you would only get two smaller dipole magnets. But what if a particle could have a single pole with a magnetic charge?

For over a century, physicists have been searching for such magnetic monopoles. A new study on the preprint server arXiv from the ATLAS collaboration at the Large Hadron Collider (LHC) places new limits on these hypothetical particles, adding new clues for the continuing search.

In 1931, physicist Paul Dirac proved that the existence of magnetic monopoles would be consistent with quantum mechanics and require—as has been observed—the quantization of the electric charge. In the 1970s, magnetic monopoles were also predicted by new theories attempting to unify all the fundamental forces of nature, inspiring physicist Joseph Polchinski to claim that their existence was “one of the safest bets that one can make about physics not yet seen.” Magnetic monopoles might have been present in the early universe but diluted to an unnoticeably tiny density during the early exponential expansion phase known as cosmic inflation.

Neutrinos, the tricky little particles that just stream through the Universe like it’s virtually nothing, may actually interact with light after all.

According to new calculations, interactions between neutrinos and photons can take place in powerful magnetic fields that can be found in the plasma wrapped around stars.

It’s a discovery that could help us understand why the Sun’s atmosphere is so much hotter than its surface, say Hokkaido University physicist Kenzo Ishikawa and Yutaka Tobita, a physicist from Hokkaido University of Science – and, of course, to study the mysterious ghost particle in greater detail.

Dark energy is believed to have a negative impact on big structures, limiting the formation of such particles.

Contrary to earlier understandings based on Einstein’s theory of general relativity, research from the University of Michigan has now found that the pace of growth of these substantial structures is slower than expected.

Large cosmic structures are predicted to expand at a certain rate as the universe expands, with galaxy clusters and other dense areas expanding faster than empty space.

Continue reading “Universe slows cosmic growth defying the theory of relativity” »

Any physical object, alive or inanimate, is composed of atoms and subatomic particles that interact in different ways governed by the principles of quantum mechanics. Some particles are in a pure state—they remain fixed and unchanged. Others are in a quantum state—a concept that can be difficult to understand because it involves having a particle occupy multiple states simultaneously. For instance, an electron in a pure state spins up or down; in a quantum state, also referred to as superposition, it spins up and down simultaneously. Another quantum principle states that particles can be in a state of entanglement in which changes in one directly affect the other. The principles of superposition and entanglement are fundamental to quantum computing.

Quantum bits, or qubits, are the smallest units of data that a quantum computer can process and store. In a pure state, qubits have a value of 1 or 0, similar to the bits used in computing today. In superposition, they can be both of these values simultaneously, and that enables parallel computations on a massive scale. While classical computers must conduct a new calculation any time a variable changes, quantum computers can explore a problem with many possible variables simultaneously.

Existing computers, although sufficient for many applications, can’t fully support all of the changes required to create a connected and intelligent-mobility ecosystem. Quantum computing (QC) could potentially provide faster and better solutions by leveraging the principles of quantum mechanics—the rules that govern how atoms and subatomic particles act and interact. (See sidebar, “Principles of quantum computing,” for more information). Over the short term, QC may be most applicable to solving complex problems involving small data sets; as its performance improves, QC will be applied to extremely large datasets.

Researchers in Germany and Japan have been able to increase the diffusion of magnetic whirls, so-called skyrmions, by a factor of ten.

In today’s world, our lives are unimaginable without computers. Up until now, these devices process information using primarily electrons as charge carriers, with the components themselves heating up significantly in the process. Active cooling is thus necessary, which comes with high energy costs. Spintronics aims to solve this problem: Instead of utilizing the electron flow for information processing, it relies on their spin or their intrinsic angular momentum. This approach is expected to have a positive impact on the size, speed, and sustainability of computers or specific components.

Magnetic whirls store and process information.

There’s a three-dimensional solution to manage the evolving dual-use concern of AI: advance states-centric monitoring and regulation, promote intellectual exchange between the non-proliferation sector and the AI industry, and encourage AI industrial contributions.