Physics News and Discussions

weatheriscool
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Physicists create platform to achieve ultra-strong photon-to-magnon coupling

by National University of Science and Technology MISIS
https://phys.org/news/2021-06-physicist ... pling.html
A team of scientists from NUST MISIS and MIPT have developed and tested a new platform for realization of the ultra-strong photon-to-magnon coupling. The proposed system is on-chip and is based on thin-film hetero-structures with superconducting, ferromagnetic and insulating layers. This discovery solves a problem that has been on the agenda of research teams from different countries for the last 10 years, and opens new opportunities in implementing quantum technologies. The study was published in the highly ranked journal Science Advances.

The last decade has seen significant progress in the development of artificial quantum systems. Scientists are exploring different platforms, each with its own advantages and disadvantages. The next critical step for advancing quantum industry requires an efficient method of information exchange between platform hybrid systems that could benefit from distinct platforms. For example, hybrid systems based on collective spin excitations, or magnons, are being developed. In such systems, magnons must interact with photons, standing electromagnetic waves trapped in a resonator. The main limiting factor for developing such systems is the fundamentally weak interaction between photons and magnons. They are of different sizes, and follow different dispersion laws. This size difference of a hundred times or more considerably complicates the interaction.
weatheriscool
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Electron-pair discovery advances field of quantum materials
https://phys.org/news/2021-06-electron- ... antum.html
by Linda Glaser, Cornell University

In 2016, physicist J.C. Séamus Davis discovered an elusive state of quantum matter in the cuprates, which are copper oxide materials laced with other atoms. That launched a new sub-field in the study of quantum materials.

But whether this was a unique phenomenon in the cuprates or a universal and important property of nature remained unknown—until now.

Using an improved version of the radically new quantum microscope technology he developed for this purpose, Davis and his team have now found the same exotic state of quantum matter in a widely used and conventional type of material, the transition metal dichalcogenides (TMD).

Their paper, "Discovery of a Cooper-pair Density Wave State in a Transition-metal Dichalcogenide," published June 25 in Science. Co-authors include Cornell postdoctoral fellows Xiaolong Liu and Yi Xue Chong, and Rahul Sharma, Ph.D. '20, a postdoc at the University of Maryland.
caltrek
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Unless one wants to argue that unidentified aerial phenomenon are a purely psychological phenomena, I think this topic belongs in the physics forum. The U.S. government certainly seems to think so. I thought that Yuli Ban had started a thread in this forum dedicated to this specific topic, by my attempt to locate such a thread using the search function came up empty. I guess that makes it an unidentified posting phenomena. :lol:

Audience: :roll:

Pentagon Releases UFO Report, Some Phenomena Still Unexplainable
by Jack Rodgers
June 25, 2021

https://www.courthousenews.com/pentagon ... plainable/

Introducing:
(Courthouse News) — A Defense Department program designed to investigate military reports of unidentified aerial phenomena, or UAPs, released its anticipated report Friday finding that the flying objects aren’t aliens, but that it isn’t quite sure what they are.

The Pentagon’s long-awaited assessment does not paint a clear picture of what service members have experienced, nor does it give definitive answers to what the objects may be.

Of the 144 sightings examined by officials as part of the report, only one was identifiable, the report notes.

A handful of those incidents — 18 of those encounters — observers describe the UAPs moving in ways uncharacteristic to present technology.

“Some UAP appeared to remain stationary in winds aloft, move against the wind, maneuver abruptly, or move at considerable speed, without discernable means of propulsion,” the report states. “In a small number of cases, military aircraft systems processed radio frequency (RF) energy associated with UAP sightings.
Image
In the image from video provided by the Department of Defense labeled Gimbal, from 2015, an unexplained object is seen at center as it is tracked as it soars high along the clouds, traveling against the wind.
(Department of Defense via AP)
weatheriscool
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The first on-chip valley-dependent quantum interference
https://phys.org/news/2021-06-on-chip-v ... antum.html
by University of Science and Technology of China
A research team led by academician Guo Guangcan from University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS), collaborating with researchers from Sun Yat-sen University and Zhejiang University, realized two-photon quantum interference in the structure of valley-dependent topological insulators based on the valley Hall effect.

The study was published in Physical Review Letters on June 11st, 2021.

Topological photonics has a practical application prospect in the research of photonic chips due to its robust energy transport prosperities. The key to topological phase transition is to generate an energy gap at certain degenerate points by breaking either the time-reversal symmetry (TRS) or inversion symmetry.
weatheriscool
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Physicists observationally confirm Hawking's black hole theorem for the first time

by Jennifer Chu, Massachusetts Institute of Technology
https://phys.org/news/2021-07-physicist ... -hole.html
There are certain rules that even the most extreme objects in the universe must obey. A central law for black holes predicts that the area of their event horizons—the boundary beyond which nothing can ever escape—should never shrink. This law is Hawking's area theorem, named after physicist Stephen Hawking, who derived the theorem in 1971.

Fifty years later, physicists at MIT and elsewhere have now confirmed Hawking's area theorem for the first time, using observations of gravitational waves. Their results appear today in Physical Review Letters.
weatheriscool
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Scientists propose new source for rare subatomic particles
https://phys.org/news/2021-07-scientist ... icles.html
by Liu Jia, Chinese Academy of Sciences
A paper based on joint research by Prof. Yuan Changzheng from Institute of High Energy Physics of the Chinese Academy of Sciences, and Prof. Marek Karliner from Tel Aviv University of Israel, was published in Physical Review Letters. It points out a new abundant source of antineutrons and hyperons. These rare subatomic particles are essential for studying forces governing the behavior of matter at the smallest distances, from atomic nuclei to neutron stars.

Physicists investigate the subatomic world by bombarding their subjects with a hail of tiny subatomic 'bullets'. Based on how these 'bullets' bounce off their target, one can infer a wealth of detailed information about the target's structure. This method was pioneered by Ernest Rutherford, who used it to discover the atomic nucleus more than 100 years ago.
weatheriscool
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Physicists take the most detailed image of atoms to date
https://www.sciencemag.org/news/2021/06 ... m=Facebook
By Anil OzaJun. 30, 2021 , 12:20 PM
Physicists just put Apple’s latest iPhone to shame, taking the most detailed image of atoms to date with a device that magnifies images 100 million times, Scientific American reports. The researchers, who set the record for the highest resolution microscope in 2018, outdid themselves with a study published last month. Using a method called electron ptychography, in which a beam of electrons is shot at an object and bounced off to create a scan that algorithms use to reverse engineer the above image, were used to visualize the sample. Previously, scientists could only use this method to image objects that were a few atoms thick. But the new study lays out a technique that can image samples 30 to 50 nanometers wide—a more than 10-fold increase in resolution, they report in Science. The breakthrough could help develop more efficient electronics and batteries, a process that requires visualizing components on the atomic level.
weatheriscool
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The pressure is off and high temperature superconductivity remains

by Nicole Johnson, University of Houston
https://phys.org/news/2021-07-pressure- ... ivity.html
In a critical next step toward room-temperature superconductivity at ambient pressure, Paul Chu, Founding Director and Chief Scientist at the Texas Center for Superconductivity at the University of Houston (TcSUH), Liangzi Deng, research assistant professor of physics at TcSUH, and their colleagues at TcSUH conceived and developed a pressure-quench (PQ) technique that retains the pressure-enhanced and/or -induced high transition temperature (Tc) phase even after the removal of the applied pressure that generates this phase.

Pengcheng Dai, professor of physics and astronomy at Rice University and his group, and Yanming Ma, Dean of the College of Physics at Jilin University, and his group contributed toward successfully demonstrating the possibility of the pressure-quench technique in a model high temperature superconductor, iron selenide (FeSe). The results were published in the journal Proceedings of the National Academy of Sciences.
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Yuli Ban
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For The First Time, Scientists Have Connected a Superconductor to a Semiconductor
The team behind the research is hoping to open up all kinds of new applications in classical and quantum physics
Scientists have succeeded in combining two exciting material types together for the very first time: an ultrathin semiconductor just a single atom thick; and a superconductor, capable of conducting electricity with zero resistance.

Both these materials have unusual and fascinating properties, and by putting them together through a delicate lab fabrication process, the team behind the research is hoping to open up all kinds of new applications in classical and quantum physics.

Semiconductors are key to the electrical gadgets that dominate our lives, from TVs to phones. What makes them so useful as opposed to regular metals is their electrical conductivity can be adjusted by applying a voltage to them (among other methods), making it easy to switch a current flow on and off.

Here, a single layer of the semiconductor molybdenum disulfide (MoS2) was extracted and added to the fabrication process.

Then we have superconductors – able to transfer an electrical charge with perfect efficiency and nothing lost to heat, when at a certain temperature (usually an extremely low one).
And remember my friend, future events such as these will affect you in the future
weatheriscool
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Quantum phase transition discovered in a quasi-2D system consisting purely of spins
https://phys.org/news/2021-07-quantum-p ... urely.html
by José Tadeu Arantes, FAPESP
Pure quantum systems can undergo phase transitions analogous to the classical phase transition between the liquid and gaseous states of water. At the quantum level, however, the particle spins in states that emerge from phase transitions display collective entangled behavior. This unexpected observation offers a new avenue for the production of materials with topological properties that are useful in spintronics applications and quantum computing.

The discovery was made by an international collaboration led by Julio Larrea, a professor at the University of São Paulo's Physics Institute (IF-USP) in Brazil. Larrea is first author of an article on the study published in Nature.

"We obtained the first experimental evidence of a first-order quantum phase transition in a quasi-two-dimensional system consisting entirely of spins. It was a groundbreaking study in terms of both experimental development and theoretical interpretation," Larrea said.
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