Physics News and Discussions

[weatheriscool]

Stable magnetic bundles achieved at room temperature and zero magnetic field
https://phys.org/news/2024-05-stable-ma ... ature.html
by Wei Wensen and Zhao Weiwei, Hefei Institutes of Physical Science, Chinese Academy of Sciences

Recently, the research team led by Prof. Du Haifeng from the High Magnetic Field laboratory at Hefei Institutes of Physical Science of the Chinese Academy of Sciences achieved stable magnetic bundles at room temperature without the need for any external magnetic field.

Their work is published in Nature Communications.

Topological magnetic structures are a type of spin arrangement with nontrivial topological properties. These structures hold promise as the next-generation data carriers and could overcome the limitations of traditional magnetic storage technologies in spintronics.

In previous research, the team proposed a method for inducing magnetic skyrmion bundles in a chiral helimagnetic material called FeGe. However, achieving stable magnetic bundles at room temperature and without an external magnetic field remained a significant challenge for practical applications in spintronics.

[weatheriscool]

Physicists create five-lane superhighway for electrons
https://phys.org/news/2024-05-physicist ... trons.html
by Elizabeth A. Thomson, Materials Research Laboratory, Massachusetts Institute of Technology

MIT physicists and colleagues have created a five-lane superhighway for electrons that could allow ultra-efficient electronics and more. The work, reported in the May 9 issue of Science, is one of several important discoveries by the same team over the last year involving a material that is essentially a unique form of pencil lead.

"This discovery has direct implications for low-power electronic devices because no energy is lost during the propagation of electrons, which is not the case in regular materials where the electrons are scattered," says Long Ju, an assistant professor in the MIT Department of Physics and corresponding author of the paper.

The phenomenon is akin to cars traveling down an open turnpike as opposed to those moving through neighborhoods. The neighborhood cars can be stopped or slowed by other drivers making abrupt stops or U-turns that disrupt an otherwise smooth commute.

[weatheriscool]

Method milestone for quantum physics: Rapid test for topological 2D materials
https://phys.org/news/2024-05-method-mi ... rapid.html
by Katja Lesser, Würzburg-Dresdner Exzellenzcluster ct.qmat

Topological quantum materials are hailed as a cornerstone of future technological advancements. Yet, validating their exceptional qualities has always been a lengthy process.

Researchers at the Cluster of Excellence ct.qmat have now developed an experimental technique that systematically identifies two-dimensional topological materials through a rapid test. This breakthrough could help accelerate the progress of this booming class of materials.

Their findings have been published in the journal Physical Review Letters.

In 2007, Professor Laurens W. Molenkamp, a founding member of the Würzburg-Dresden Cluster of Excellence ct.qmat—Complexity and Topology in Quantum Matter—provided the first experimental proof of topological insulators, a novel class of materials. These materials stand out because although their interior behaves like an electrical insulator, they conduct electrons on their surface without any resistance.

[weatheriscool]

Researchers develop world's smallest quantum light detector on a silicon chip
https://phys.org/news/2024-05-world-sma ... licon.html
by University of Bristol

The silicon ePIC quantum chip, mounted on a printed circuit board for testing and similar to a motherboard inside a personal computer. Credit: University of Bristol

Researchers at the University of Bristol have made an important breakthrough in scaling quantum technology by integrating the world's tiniest quantum light detector onto a silicon chip. The paper, "A Bi-CMOS electronic photonic integrated circuit quantum light detector," was published in Science Advances.

A critical moment in unlocking the information age was when scientists and engineers were first able to miniaturize transistors onto cheap micro-chips in the 1960s.

[weatheriscool]

Researchers realize multiphoton electron emission with non-classical light
https://phys.org/news/2024-05-multiphot ... sical.html
by Ingrid Fadelli , Phys.org

Strong field quantum optics is a rapidly emerging research topic, which merges elements of non-linear photoemission rooted in strong field physics with the well-established realm of quantum optics. While the distribution of light particles (i.e., photons) has been widely documented both in classical and non-classical light sources, the impact of such distributions on photoemission processes remains poorly understood.

Researchers at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) and the Max Planck Institute for the Science of Light recently set out to fill this gap in the literature, by exploring the interactions between light and matter with a non-classical light source. Their paper, published in Nature Physics, demonstrates that photon statistics of the driving light source are imprinted on the electron number statistics of emitted electrons from metal needle tips, an observation that could have interesting implications for the future development of optical devices.

[weatheriscool]

New method can create aquatic levitation at much lower temperature, has implications for cooling nuclear reactors
https://phys.org/news/2024-05-method-aq ... tions.html
by Virginia Tech

Splash a few drops of water on a hot pan and if the pan is hot enough, the water will sizzle and the droplets of water seem to roll and float, hovering above the surface.

The temperature at which this phenomenon, called the Leidenfrost effect, occurs is predictable, usually happening above 230 degrees Celsius. The team of Jiangtao Cheng, associate professor in the Virginia Tech Department of Mechanical Engineering, has discovered a method to create the aquatic levitation at a much lower temperature, and the results have been published in Nature Physics.

[firestar464]

Researchers detect hidden threats with advanced X-ray imaging

https://techxplore.com/news/2024-05-hid ... aging.html

If there's a better thread for this please let me know.

[Powers]

Researchers detect hidden threats with advanced X-ray imaging

https://techxplore.com/news/2024-05-hid ... aging.html

If there's a better thread for this please let me know.

This.

[firestar464]

Quantum time travel: The experiment to 'send a particle into the past'- New Scientist

https://archive.ph/WTfue

[firestar464]

Disputed dark-matter claim to be tested by new lab in South Korea

https://www.nature.com/articles/d41586-024-01347-3

[weatheriscool]

News from 'El Gordo': Study suggests dark matter may have collisional properties after all
https://phys.org/news/2024-05-news-el-g ... ional.html
by International School of Advanced Studies (SISSA)

Contrary to what is established by the standard model, dark matter may indeed be self-interacting. This was the conclusion of a piece of research published in Astronomy & Astrophysics and conducted by Riccardo Valdarnini of SISSA's Astrophysics and Cosmology group. Using numerical simulations, the study analyzed what happens inside "El Gordo" (literally "The Fat One" in Spanish), a giant cluster merger seven billion light years away from us.

[weatheriscool]

Physicists take molecules to a new ultracold limit, creating a state of matter where quantum mechanics reigns
https://phys.org/news/2024-06-physicist ... state.html
by Ellen Neff, Columbia University

There's a hot new BEC in town that has nothing to do with bacon, egg, and cheese. You won't find it at your local bodega, but in the coldest place in New York: the lab of Columbia physicist Sebastian Will, whose experimental group specializes in pushing atoms and molecules to temperatures just fractions of a degree above absolute zero.

Writing in Nature, the Will lab, supported by theoretical collaborator Tijs Karman at Radboud University in the Netherlands, has successfully created a unique quantum state of matter called a Bose-Einstein Condensate (BEC) out of molecules.

Their BEC, cooled to just five nanoKelvin, or about -459.66°F, and stable for a strikingly long two seconds, is made from sodium-cesium molecules. Like water molecules, these molecules are polar, meaning they carry both a positive and a negative charge. The imbalanced distribution of electric charge facilitates the long-range interactions that make for the most interesting physics, noted Will.

[firestar464]

New insights on the role of nucleon exchange in nuclear fusion

https://phys.org/news/2024-06-insights- ... clear.html

[weatheriscool]

Physicists confirm quantum entanglement persists between top quarks, the heaviest known fundamental particles
https://phys.org/news/2024-06-physicist ... uarks.html
by David Andreatta, University of Rochester

An experiment by a group of physicists led by University of Rochester physics professor Regina Demina has produced a significant result related to quantum entanglement—an effect that Albert Einstein called "spooky action at a distance."

Entanglement concerns the coordinated behavior of miniscule particles that have interacted but then moved apart. Measuring properties—like position or momentum or spin—of one of the separated pair of particles instantaneously changes the results of the other particle, no matter how far the second particle has drifted from its twin. In effect, the state of one entangled particle, or qubit, is inseparable from the other.

Quantum entanglement has been observed between stable particles, such as photons or electrons.

[Time_Traveller]

‘It’s the perfect place’: London Underground hosts tests for ‘quantum compass’ that could replace GPS

Sat 15 Jun 2024 15.58 BST

Dr Joseph Cotter takes some unusual pieces of luggage on his trips on the London underground. They include a stainless steel vacuum chamber, a few billion atoms of rubidium and an array of lasers that are used to cool his equipment to a temperature just above absolute zero.

While not the average kit you would expect to find being dragged into carriages on the District Line, this is the gear that Cotter – who works at Imperial College London’s Centre for Cold Matter – uses on his underground travels.

Though the baggage may be bizarre, it has an ambitious purpose. It is being used to develop a quantum compass – an instrument that will exploit the behaviour of subatomic matter in order to develop devices that can accurately pinpoint their locations no matter where they are placed, paving the way for the creation of a new generation of underground and underwater sensors.

The ideal place to test it is the London underground, Cotter and his team have discovered. “We are developing very precise new sensors using quantum mechanics, and these are showing great promise in the laboratory,” he told the Observer last week. “However, they are less accurate in real-life settings. That is why we are taking our equipment to the London underground. It’s the perfect place for smoothing out the rough edges and getting our equipment to work in real life.”

The idea of a quantum compass is to bypass or augment current methods for pinpointing the locations of planes, cars and other objects. These usually rely on global navigation satellite systems (GNSS) – such as GPS – which have become crucial in the transport of goods and services by road, sea and air. By using external signals, these systems can precisely fix the positions of vehicles.

https://www.theguardian.com/science/art ... -locations

[weatheriscool]

Scientists develop 3D printed vacuum system that aims to trap dark matter
https://phys.org/news/2024-06-scientist ... -dark.html
by University of Nottingham

Using a specially designed 3D printed vacuum system, scientists have developed a way to "trap" dark matter with the aim of detecting domain walls. This will be a significant step forwards in unraveling some of the mysteries of the universe.

Scientists from the University of Nottingham's' School of Physics have created a 3D printed vacuum system that they will use in a new experiment to reduce the density of gas, and then add in ultra-cold lithium atoms to try to detect dark walls. The research has been published in Physical Review D.

Professor Clare Burrage from the School of Physics is one of the lead authors on the study and explains, "Ordinary matter that the world is made from is only a tiny fraction of the contents of the universe, around 5%, the rest is either dark matter or dark energy—we can see their effects on how the universe behaves but we don't know what they are. One way people try to measure dark matter is to introduce a particle called a scalar field."

[firestar464]

Time May Actually Be One Big Illusion, Says a New Study

https://www.msn.com/en-ca/news/technolo ... r-BB1oo8uj

[weatheriscool]

A method to reversibly control Casimir forces using external magnetic fields
https://phys.org/news/2024-06-method-re ... netic.html
by Ingrid Fadelli , Phys.org

The so-called Casimir force or Casimir effect is a quantum mechanical phenomenon resulting from fluctuations in the electromagnetic field between two conducting or dielectric surfaces that are a short distance apart. Studies have shown that this force can be either be attractive or repulsive, depending on the dielectric and magnetic properties of the materials used in experiments.

Researchers at University of Science and Technology of China have recently been exploring the possibility of selectively tuning the Casimir force, in other words switching it from attractive to repulsive and vice-versa, using external magnetic fields. Their study, featured in Nature Physics, demonstrates the successful magnetic field-tuning of the Casimir force arising from a gold sphere and silica plate immersed in water-based ferrofluids.

[weatheriscool]

Researchers develop platform to probe, control qubits in silicon for quantum networks
https://phys.org/news/2024-06-platform- ... antum.html
by Leah Burrows, Harvard John A. Paulson School of Engineering and Applied Sciences

The quantum internet would be a lot easier to build if we could use existing telecommunications technologies and infrastructure. Over the past few years, researchers have discovered defects in silicon—a ubiquitous semiconductor material—that could be used to send and store quantum information over widely used telecommunications wavelengths. Could these defects in silicon be the best choice among all the promising candidates to host qubits for quantum communications?

"It's still a Wild West out there," said Evelyn Hu, the Tarr-Coyne Professor of Applied Physics and of Electrical Engineering at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS).

"Even though new candidate defects are a promising quantum memory platform, there is often almost nothing known about why certain recipes are used to create them, and how you can rapidly characterize them and their interactions, even in ensembles.

[weatheriscool]

The design of a photonic alloy with topological properties
https://phys.org/news/2024-06-photonic- ... rties.html
by Ingrid Fadelli , Phys.org

Photonic alloys, alloy-like materials combining two or more photonic crystals, are promising candidates for the development of structures that control the propagation of electromagnetic waves, also known as waveguides. Despite their potential, these materials typically reflect light back in the direction where it originated.

This phenomenon, known as light backscattering, limits the transmission of data and energy, adversely impacting the materials' performance as waveguides. Reliably reducing or preventing light backscattering in photonic alloys will thus be a key milestone towards the practical use of these materials.