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Category: particle physics – Page 265

Revolutionizing Electronics: Physicists Achieve Major Advance Using Graphene Spintronics

Physicists at the National University of Singapore have innovated a concept to induce and directly quantify spin splitting in two-dimensional materials. By using this concept, they have experimentally achieved large tunability and a high degree of spin-polarisation in graphene. This research achievement can potentially advance the field of two-dimensional (2D) spintronics, with applications for low-power electronics.

Joule heating poses a significant challenge in modern electronics, especially in devices such as personal computers and smartphones. This is an effect that occurs when the flow of electrical current passing through a material produces thermal energy, subsequently raising the material’s temperature.

One potential solution involves the use of spin, instead of charge, in logic circuits. These circuits can, in principle, offer low-power consumption and ultrafast speed, owing to the reduction or elimination of Joule heating. This has given rise to the emerging field of spintronics.

Is a black hole stuck inside the sun? No, but here’s why scientists are asking

To that end, Caplan is part of a crew that posits the dark matter portion of the dark universe could very well be made up of not particles like we imagine, but instead a huge number of atom-size black holes produced during the dawn of the universe, each of which is about as massive as a typical asteroid in our own solar system. “I think all dark matter candidates are just a little bit wild,” Caplan, who is an assistant professor of physics at Illinois State University, told Space.com. “Some guesses are better than others, and primordial black holes are taken seriously. I’ll go so far as to say I think they’re popular.”

But to turn the hypothesis into fact, he says, scientists have to actually find one of these miniscule ancient voids — which brings us to this new black-hole-sun conversation. Potentially, Caplan and his co-authors say in their papers, some of those ultrasmall black holes might’ve gotten caught up in dust clouds in the midst of forming stars. Potentially, they might’ve ended up literally lodged in those eventual sparkling oceans of plasma. Potentially, they might still be there.

So, no, there is probably not a black hole in the center of our star — but there might be other stars gallivanting through space with black holes indeed wedged within their hearts.

Quantum physicist photographs a single atom you can see with the naked eye

Ever think you’d see a single atom without staring down the barrel of a powerful microscope? Oxford University physicist David Nadlinger has won the top prize in the fifth annual Engineering and Physical Sciences Research Council’s (EPSRC) national science photography competition for his image ‘Single Atom in an Ion Trap’, which does something incredible: makes a single atom visible to the human eye.

Click image to zoom. Photo: David Nadlinger/EPSRC

Captured on an ordinary digital camera, the image shows an atom of strontium suspended by electric fields emanating from the metal electrodes of an ion trap—those electrodes are about 2mm apart. Nadlinger shot the photo through the window of the ultra-high vacuum chamber that houses the ion trap, which is used to explore the potential of laser-cooled atomic ions in new applications such as highly accurate atomic clocks and sensors, and quantum computing.

A method to straighten curved space-time

One of the greatest challenges of modern physics is to find a coherent method for describing phenomena, on the cosmic and microscale. For over a hundred years, to describe reality on a cosmic scale we have been using general relativity theory, which has successfully undergone repeated attempts at falsification.

Albert Einstein curved space-time to describe gravity, and despite still-open questions about or , it seems, today, to be the best method of analyzing the past and future of the universe.

To describe phenomena on the scale of atoms, we use the second great theory: , which differs from general relativity in basically everything. It uses flat space-time and a completely different mathematical apparatus, and most importantly, perceives reality radically differently.

Breaking the 10-petawatt limit with a new laser amplification

Ultra-intense ultrashort lasers have a wide-ranging scope of applications, encompassing basic physics, national security, industrial service, and health care. In basic physics, such lasers have become a powerful tool for researching strong-field laser physics, especially for laser-driven radiation sources, laser particle acceleration, vacuum quantum electrodynamics, and more.

A dramatic increase in peak power, from the 1996 1-petawatt “Nova” to the 2017 10-petawatt “Shanghai Super-intense Ultrafast Laser Facility” (SULF) and the 2019 10-petawatt “Extreme Light Infrastructure—Nuclear Physics” (ELI-NP), is due to a shift in gain medium for large-aperture lasers (from neodymium-doped glass to titanium: crystal). That shift reduced the pulse duration of high-energy lasers from around 500 femtoseconds (fs) to around 25 fs.

However, the for titanium: sapphire ultra-intense ultrashort lasers appears to be 10-petawatt. Presently, for 10-petawatt to 100-petawatt development planning, researchers generally abandon the titanium: sapphire chirped pulse technology, and turn to optical parametric chirped pulse amplification technology, based on deuterated potassium dihydrogen phosphate nonlinear crystals. That technology, due to its low pump-to-signal conversion efficiency and poor spatiotemporal-spectral-energy stability, will pose a great challenge for the realization and application of the future 10–100 petawatt lasers.

Hunting for elusive tetraneutrons with thermal fission

The possible emission rate of particle-stable tetraneutron, a four-neutron system whose existence has been long debated within the scientific community, has been investigated by researchers from Tokyo Tech. They looked into tetraneutron emission from thermal fission of 235 U by irradiating a sample of 88 SrCO3 in a nuclear research reactor and analyzing it via γ-ray spectroscopy.

Tetraneutron is an elusive atomic nucleus consisting of four neutrons, whose existence has been highly debated by scientists. This stems primarily from our lack of knowledge about systems consisting of only neutrons, since most are usually made of a combination of protons and neutrons. Scientists believe that the experimental observation of a tetraneutron could be the key to exploring new properties of atomic nuclei and answering the age-old question: Can a charge-neutral multineutron system ever exist?

Two recent experimental studies reported the presence of tetraneutrons in bound state and resonant state (a state that decays with time but lives long enough to be detected experimentally). However, indicate that tetraneutrons will not exist in a bound state if the interactions between neutrons are governed by our common understanding of two or three-body nuclear forces.

New insights on how light interacts with magnets for better sensors and memory tech

Professor Amir Capua, head of the Spintronics Lab within the Institute of Applied Physics and Electrical Engineering at Hebrew University of Jerusalem, announced a pivotal breakthrough in the realm of light-magnetism interactions. The team’s unexpected discovery reveals a mechanism wherein an optical laser beam controls the magnetic state in solids, promising tangible applications in various industries.

“This breakthrough marks a in our understanding of the interaction between light and magnetic materials,” stated Professor Capua. “It paves the way for light-controlled, high-speed memory technology, notably Magnetoresistive Random Access Memory (MRAM), and innovative optical sensor development. In fact, this discovery signals a major leap in our understanding of light-magnetism dynamics.”

The research challenges conventional thinking by unraveling the overlooked magnetic aspect of light, which typically receives less attention due to the slower response of magnets compared to the rapid behavior of light radiation.

NASA telescopes start tҺe year witҺ a double bang

A colorful, festive image sҺows different types of ligҺt containing tҺe remains of not one, but at least two exploded stars. TҺis supernova remnant is ƙnown as 30 Doradus B (30 Dor B for sҺort) and is part of a larger region of space wҺere stars Һave been continuously forming for tҺe past 8 to 10 million years. It is a complex landscape of darƙ clouds of gas, young stars, ҺigҺ-energy sҺocƙs, and superҺeated gas, located 160,000 ligҺt-years away from EartҺ in tҺe Large Magellanic Cloud, a small satellite galaxy of tҺe Milƙy Way.

TҺe new image of 30 Dor B was made by combining X-ray data from NASA’s CҺandra X-ray Observatory (purple), optical data from tҺe Blanco 4-meter telescope in CҺile (orange and cyan), and infrared data from NASA’s Spitzer Space Telescope (red). Optical data from NASA’s Hubble Space Telescope was also added in blacƙ and wҺite to ҺigҺligҺt sҺarp features in tҺe image.

A team of astronomers led by Wei-An CҺen from tҺe National Taiwan University in Taipei, Taiwan, Һave used over two million seconds of CҺandra observing time of 30 Dor B and its surroundings to analyze tҺe region. TҺey found a faint sҺell of X-rays tҺat extends about 130 ligҺt-years across. (For context, tҺe nearest star to tҺe sun is about four ligҺt-years away). TҺe CҺandra data also reveals tҺat 30 Dor B contains winds of particles blowing away from a pulsar, creating wҺat is ƙnown as a pulsar wind nebula.

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