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Category: particle physics – Page 28

Stacked quantum materials enable precise spin control without external magnetic fields

Spintronics—a technology that harnesses the electron’s magnetic quantum states to carry information—could pave the way for a new generation of ultra-energy-efficient electronics. Yet a major challenge has been the ability to control these delicate quantum properties with sufficient precision for practical applications. By combining different quantum materials, researchers at Chalmers University of Technology have now taken a decisive step forward, achieving unprecedented control over spin phenomena. The advance opens the door to next-generation low-power data processing and memory technologies.

Data centers, cloud services, AI and connected systems account for a rapidly growing share of global energy consumption. In the quest for new, more energy-efficient technological solutions, spin electronics, or spintronics, has proven to be a new and promising approach. Instead of relying solely on the movement of electric charge, spintronics use magnetic states to carry information. More specifically, it takes advantage of a quantum property of electrons known as spin, which makes electrons behave like tiny magnets.

“Just like a compass needle, an electron’s spin can point in one of two directions—up or down. These two directions can be used to represent digital information, in the same way today’s electronics use 0s and 1s,” explains Saroj Dash, Professor of Quantum Device Physics at Chalmers University of Technology.

Chemical shifts help track molecules breaking apart in real time

When molecules fall apart, their electric charge doesn’t stay put—it rearranges as bonds stretch and break. An international team of scientists has now tracked these ultrafast changes in the small molecule fluoromethane (CH₃F). It was the first time that the Small Quantum Systems (SQS) instrument at European XFEL could deliver detailed insights into transient states during chemical reactions. The research is published in the journal Physical Review X.

These intermediate states, that only exist temporarily while the reaction is ongoing, are often the key drivers of chemistry and therefore crucial to understand. Over the long term, that kind of insight can support progress in areas such as atmospheric science (where sunlight-driven reactions and fragmentation pathways shape air chemistry), as well as the study of complex molecular systems including biomolecules and proteins, where local excitation and charge transfer can trigger structural change.

In the experiment, the researchers first triggered the reaction with an optical laser pulse. Next, they used the X-ray laser pulses that the European XFEL produces, to eject an electron from the core of either the fluorine or the carbon atom in the molecule. They measured the electron’s kinetic energy, which reveals how strongly it was bound inside the atom. That binding energy is extremely sensitive to the local electrical environment, producing so-called “chemical shifts” that act like a fingerprint of the charge distribution surrounding the atom from which the electron has been ejected.

Precisely measuring quantum signals in large spin ensembles

Quantum mechanical effects are known to be easily disrupted by disturbances from the surrounding environment, commonly referred to as noise. To minimize these disturbances, physicists often study these effects in small and carefully controlled systems, in which environmental noise can be minimized.

Researchers at Johns Hopkins University set out to study quantum effects in macroscopic spin ensembles, systems comprised of large numbers of spins (spins is the intrinsic angular momentum of elementary particles). Their paper, published in Nature Physics, introduces a new approach to directly observe quantum spin fluctuations in macroscopic spin ensembles, precisely monitoring their evolution over time.

“Quantum effects are typically observed and exploited in microscopic systems, where individual qubits can be precisely controlled and measured,” Alexander O. Sushkov, senior author of the paper, told Phys.org.

3D imaging reveals messy-looking supraparticles can be nearly perfect crystals inside

Researchers at Utrecht University have quantitatively mapped the three-dimensional structure of photonic supraparticles for the first time. Supraparticles are microscopic spheres composed of thousands of smaller colloidal particles. Until now, researchers could only examine the outer surface of these structures. Using a combination of super-resolution microscopy and machine learning, the team shows that particles that appear disorganized on the outside are often almost perfectly crystalline on the inside.

The paper is published in the journal Advanced Materials.

Blue morpho butterflies owe their vibrant color to the internal structure of their wings, rather than pigment. The arrangement of particles on a microscopic scale causes light to be reflected in such a way that the butterflies appear intensely blue, and that the color looks the same from every viewing angle.

How does snow gather on a roof? Simulation considers turbulence alongside snowflake size

No two snowflakes may be the same, but models that fail to take these variations into consideration often fall short when calculating the way snow accumulates on roofs. In Physics of Fluids, researchers from Harbin Institute of Technology in China modeled the way snow gathers on a roof based on snowflake size and distribution.

“In cold regions, snow load is a critical factor in structural design,” said author Qingwen Zhang. “However, traditional models often simplify snow as a uniform material with a single particle size, overlooking the natural heterogeneity of snowflake sizes and distributions.”

Largest ever radio sky survey maps the universe in unprecedented detail

An international collaboration using the Low Frequency Array (LOFAR) has published an exceptionally detailed radio sky map, revealing 13.7 million cosmic sources and delivering the most complete census yet of actively growing supermassive black holes. It showcases an extraordinary variety of systems powered by these black holes, whose radio emission can extend for millions of light-years.

The newly released LOFAR Two-meter Sky Survey (LoTSS-DR3) marks a major milestone in radio astronomy and international scientific collaboration. The results will be published in Astronomy & Astrophysics.

By observing the sky at low radio frequencies, the survey reveals a dramatically different view of the universe than that seen at optical wavelengths. Much of the detected emission arises from relativistic particles moving through magnetic fields, allowing astronomers to trace energetic phenomena such as powerful jets from supermassive black holes and galaxies undergoing extreme star formation across cosmic time.

Strontium optical clock accurate to within 1 second over 30 billion years

Researchers from the University of Science and Technology of China have achieved a major breakthrough in optical clock technology, developing a strontium optical lattice clock with stability and uncertainty both surpassing the 10⁻¹⁹ level, meaning the clock would lose or gain less than one second over roughly 30 billion years.

The findings are published in the journal Metrologia.

Optical clocks are considered the most precise timekeeping devices currently available. They measure time by using the frequency of light emitted when electrons transition between energy levels in atoms.

A perfectly balanced atom just broke one of nuclear physics’ biggest rules

Physicists have discovered a surprising new “Island of Inversion” in a place no one expected: among nuclei where the number of protons equals the number of neutrons. For decades, these strange regions—where atomic nuclei abandon their usual orderly structure and become strongly deformed—were thought to exist only in highly neutron-rich isotopes far from stability. But experiments on molybdenum isotopes revealed that molybdenum-84 behaves dramatically differently from its close neighbor molybdenum-86, even though they differ by just two neutrons.

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