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Category: particle physics – Page 185

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.

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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.

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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.

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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.

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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.

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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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Astronomers from the Western Sydney University in Australia and elsewhere report the detection of a new pulsar wind nebula and a pulsar that powers it. The discovery, presented in a paper published Dec. 12 on the pre-print server arXiv, was made using the Australian Square Kilometer Array Pathfinder (ASKAP), as well as MeerKAT and Parkes radio telescopes.

Pulsar wind nebulae (PWNe) are nebulae powered by the wind of a pulsar. Pulsar wind is composed of charged particles; when it collides with the pulsar’s surroundings, in particular with the slowly expanding supernova ejecta, it develops a PWN.

Particles in PWNe lose their energy to radiation and become less energetic with distance from the central pulsar. Multiwavelength studies of these objects, including X-ray observations, especially using spatially-integrated spectra in the X-ray band, have the potential to uncover important information about particle flow in these nebulae. This could unveil important insights into the nature of PWNe in general.

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Researchers at the Georgia Institute of Technology have created the world’s first functional semiconductor made from graphene, a single sheet of carbon atoms held together by the strongest bonds known. Semiconductors, which are materials that conduct electricity under specific conditions, are foundational components of electronic devices. The team’s breakthrough throws open the door to a new way of doing electronics.

Their discovery comes at a time when , the material from which nearly all modern electronics are made, is reaching its limit in the face of increasingly faster computing and smaller electronic devices.

Walter de Heer, Regents’ Professor of physics at Georgia Tech, led a team of researchers based in Atlanta, Georgia, and Tianjin, China, to produce a semiconductor that is compatible with conventional microelectronics processing methods—a necessity for any viable alternative to silicon.

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