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Ultrafast spectroscopy reveals step-by-step energy flow in germanium semiconductors

Whether in a smartphone or laptop, semiconductors form the basis of modern electronics and accompany us constantly in everyday life. The processes taking place inside these materials are the subject of ongoing research. When the electrons in a semiconductor material are activated using light or an electrical voltage, the excited electrons also set the atomic lattice in motion. This results in collective vibrations of the atoms, known as phonons or lattice vibrations, which interact with each other and with the electrons themselves.

These tiny lattice vibrations play a vital role in how energy flows and dissipates through the material—in other words, in how efficiently the energy is redistributed and how strongly the material heats up. Different approaches can be used to control and monitor the propagation of lattice vibrations—and therefore to make the semiconductor more effective and more efficient.

Detailed knowledge of the mechanisms of energy loss and potential overheating is essential in order to design new materials and devices that heat up less, recover faster or respond to external excitation more precisely. A team led by Professor Ilaria Zardo from the University of Basel reports on the unprecedented accuracy they achieved in measurements of energy flow processes within the semiconductor germanium, which is frequently used in computer technology. Their paper is published in Advanced Science.

First direct evidence of Migdal effect opens new path for dark matter search

In a landmark discovery that bridges nearly a century of theoretical physics, a Chinese research team has successfully captured the first direct evidence of the Migdal effect, a breakthrough with profound implications for probing dark matter—the invisible substance thought to make up roughly 85% of the universe.

The finding, published in the journal Nature, confirms a prediction made in 1939 by Soviet physicist Arkady Migdal: When an atomic nucleus suddenly gains energy—for instance, from a collision with a neutral particle (like a neutron or a dark matter candidate)—and recoils, the rapid shift in the atom’s internal electric field can eject one of its orbiting electrons.

For nearly nine decades, this “electron ejection” process remained purely theoretical. Direct evidence proved elusive because the effect occurs on an incredibly tiny scale and is easily masked by background noise from cosmic rays and natural radiation.

Observing the positronium beam as a quantum matter wave for the first time

One of the discoveries that fundamentally distinguished the emerging field of quantum physics from classical physics was the observation that matter behaves differently at the smallest scales. A key finding was wave-particle duality, the revelation that particles can exhibit wave-like properties.

This duality was famously demonstrated in the double-slit experiment. When electrons were fired through two slits, they created an interference pattern of light and dark fringes on a detector. This pattern showed that each electron behaved like a wave, with its quantum wave-function passing through both slits and interfering with itself. The same phenomenon was later confirmed for neutrons, helium atoms, and even large molecules, making matter-wave diffraction a cornerstone of quantum mechanics.

Copenhagen Researchers state the Universe responds to our Actions Even Retroactively

The copenhagen interpretation & retroactivity. quantum mechanics basics:

Particles exist in a superposition of states until observed.

Measurement “collapses” the wave function into a definite outcome.

Retrocausality Debate:

Some physicists have explored whether quantum events can appear to be influenced by future measurements.

This is sometimes described as the universe “responding retroactively,” but it’s a controversial interpretation, not mainstream science.

Distorted honeycomb magnet edges closer to a quantum spin liquid

Neutron scattering and simulations reveal why a promising Kitaev candidate freezes into order instead of forming a quantum spin liquid.


Most magnets are predictable. Cool them down, and their tiny magnetic moments snap into place like disciplined soldiers. However, physicists have long suspected that, under the right conditions, magnetism might refuse to settle even in extreme cold.

This restless state, known as a quantum spin liquid, could unlock new kinds of particles and serve as a foundation for quantum technologies that are far more stable than today’s fragile systems.

At Oak Ridge National Laboratory (ORNL), researchers have now created and closely examined a new magnetic material that brings this strange possibility a little closer to reality, even if it doesn’t quite cross the finish line yet.

Modern Calculations Finally Solve 50-Year-Old Magnetic Mystery in Steel

Researchers at the Department of Materials Science and Engineering within The Grainger College of Engineering have identified the first detailed physical mechanism explaining how magnetic fields slow the movement of carbon atoms inside iron. The study, published in Physical Review Letters, sheds new light on the role carbon plays in shaping the internal grain structure of steel.

Steel, which is made from iron and carbon, is among the most widely used construction materials worldwide. Producing steel with specific internal structures typically requires extreme heat, making the process highly energy intensive.

Decades ago, researchers observed that exposing certain steels to magnetic fields during heat treatment led to improved performance, but the explanations offered at the time remained largely theoretical. Pinpointing the underlying cause of this effect could give engineers more precise control over heat treatment, leading to more efficient processing and lower energy demands.

SPHEREx Images and a New Anomaly Regarding the Gas Plume Around 3I/ATLAS After Perihelion

A new paper led by Carey Lisse (accessible here) reports large-scale images of the gas plume around the interstellar object 3I/ATLAS after perihelion, based on data collected last month by the SPHEREx space observatory. The data show enhanced mass loss of dust and gas around 3I/ATLAS.

The new images of 3I/ATLAS were taken in the wavelength range of 0.75–5.0 microns between the 8 and 15 of December, 2025. Each image spans 30,000 kilometers on a side. On these large scales, the brightness maps of dust and organics were found to be pear-shaped, with an anti-tail elongation in the direction of the Sun. All six other gas plumes were found to be nearly round. The major gas species were identified as: cyanide (CN, at a wavelength of 0.93 microns), water (H2O, in the wavelength range of 2.7–2.8 microns), Organics (C-H, between 3.2–3.6 microns), carbon-dioxide (CO2, 4.2–4.3 microns), and carbon-monoxide (CO, 4.7–4.8 microns). The CO2 gas-plume continues to extend out to a few hundreds of thousands of kilometers. The dust spectrum can be described as the sum of scattered sunlight and thermal emission.

Most notably, the signature of sub-micron dust particles that would have enhanced the blue color via Rayleigh scattering are absent. Moreover, these small particles would have also been subjected to a strong solar radiation-pressure and would have formed the standard cometary tail, extending away from the Sun — which is not observed — as I argued in an essay, posted here on December 25, 2026.

Magnetic fields slow carbon migration in iron by altering energy barriers, study shows

Professor Dallas Trinkle and colleagues have provided the first quantitative explanation for how magnetic fields slow carbon atom movement through iron, a phenomenon first observed in the 1970s but never fully understood. Published in Physical Review Letters, their computer simulations reveal that magnetic field alignment changes the energy barriers between atomic “cages,” offering potential pathways to reduce the energy costs and CO2 emissions associated with steel processing.

An alloy of iron and carbon, steel is one of the most-used building materials on the planet. Engineering its microstructure requires high temperatures; as a result, most steel processing consumes significant energy. In the 1970s, scientists noted that some steels exhibited better properties when heat treated under a magnetic field—but their ideas explaining this behavior were only conceptual. Understanding the mechanism behind this phenomenon could improve engineers’ ability to control heat treatment, improving material processing and potentially lowering energy costs.

“The previous explanations for this behavior were phenomenological at best,” said Trinkle, the Ivan Racheff Professor of Materials Science and Engineering and the senior author of the paper. “When you’re designing a material, you need to be able to say, ‘If I add this element, this is how (the material) will change.’ And we had no understanding of how this was happening; there was nothing predictive about it.”

Imaging technique captures ultrafast electron and atom dynamics in chemical reactions

During chemical reactions, atoms in the reacting substances break their bonds and re-arrange, forming different chemical products. This process entails the movement of both electrons (i.e., negatively charged particles) and nuclei (i.e., the positively charged central parts of atoms). Valence electrons are shared and re-arranged between different atoms, creating new bonds.

The movements of electrons and nuclei during chemical reactions are incredibly fast, in many cases only lasting millionths of a billionth of a second (i.e., femtoseconds). Yet reliably tracking and understanding these movements could help to shed new light on how specific molecules are formed, as well as on the underpinnings of quantum mechanical phenomena.

Researchers at Shanghai Jiao Tong University recently introduced a new approach to observe chemical reactions as they unfold, precisely tracking the movement of electrons and atomic nuclei as a molecule breaks apart. This strategy, outlined in a paper published in Physical Review Letters, was successfully used to image the photodissociation of ammonia (NH₃), the process in which a NH₃ molecule absorbs light and breaks down into smaller pieces.

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