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Category: physics – Page 6

AI tensor network-based computational framework cracks a 100-year-old physics challenge

Researchers from The University of New Mexico and Los Alamos National Laboratory have developed a novel computational framework that addresses a longstanding challenge in statistical physics.

The Tensors for High-dimensional Object Representation (THOR) AI framework employs tensor network algorithms to efficiently compress and evaluate the extremely large configurational integrals and central to determining the thermodynamic and mechanical properties of materials.

The framework was integrated with machine learning potentials, which encode interatomic interactions and dynamical behavior, enabling accurate and scalable modeling of materials across diverse physical conditions.

Gaia solves mystery of tumbling asteroids and finds new way to probe their interiors

Whether an asteroid is spinning neatly on its axis or tumbling chaotically, and how fast it is doing so, has been shown to be dependent on how frequently it has experienced collisions. The findings, presented at the recent EPSC-DPS2025 Joint Meeting in Helsinki, are based on data from the European Space Agency’s Gaia mission and provide a means of determining an asteroid’s physical properties—information that is vital for successfully deflecting asteroids on a collision course with Earth.

“By leveraging Gaia’s unique dataset, advanced modeling and A.I. tools, we’ve revealed the hidden physics shaping rotation, and opened a new window into the interiors of these ancient worlds,” said Dr. Wen-Han Zhou of the University of Tokyo, who presented the results at EPSC-DPS2025.

During its survey of the entire sky, the Gaia mission produced a huge dataset of asteroid rotations based on their light curves, which describe how the light reflected by an asteroid changes over time as it rotates. When the asteroid data is plotted on a graph of the rotation period versus diameter, something startling stands out—there’s a gap, or dividing line that appears to split two distinct populations.

Demonstration of a next-generation wavefront actuator for gravitational-wave detection

In the last decade, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the European Virgo Observatory have opened a new observational window on the universe. These cavity-enhanced laser interferometers sense spacetime strain, generated by distant astrophysical events such as black hole mergers, to an RMS fluctuation of a few parts in 1021 over a multi-kilometer baseline. Optical advancements in laser wavefront control are key to advancing the sensitivity of current detectors and enabling a planned next-generation 40 km gravitational wave observatory in the United States, known as Cosmic Explorer. We report an experimental demonstration of a wavefront control technique for gravitational-wave detection, obtained from testing a full-scale prototype on a 40 kg LIGO mirror. Our results indicate that this design can meet the unique and challenging requirements of providing higher-order precision wavefront corrections at megawatt laser power levels while introducing extremely low effective displacement noise into the interferometer. This technology will have a direct and enabling impact on the observational science, expanding the gravitational-wave detection horizon to very early times in the universe, before the first stars formed, and enabling new tests of gravity, cosmology, and dense nuclear matter.

Physicists realize time-varying strong coupling in a magnonic system

Time-varying systems, materials with properties that change over time, have opened new possibilities for the experimental manipulation of waves. Contrarily to static systems, which exhibit the same properties over time, these materials break so-called temporal translation symmetry. This in turn prompts the emergence of various fascinating phenomena, including time reflection, refraction and diffraction.

Scientists Discover “Virtual Charges” That Exist Only When Light Hits

A study led by Politecnico di Milano, recently published in Nature Photonics, highlights the crucial role of virtual charges in insulating materials. One of the biggest challenges in modern physics and photonics is understanding how materials behave when struck by extremely brief flashes of light

New adaptive optics system promises sharper gravitational-wave observations

Gravitational-wave detection technology is poised to make a big leap forward thanks to an instrumentation advance led by physicist Jonathan Richardson of the University of California, Riverside. A paper detailing the invention, published in the journal Optica, reports the successful development and testing of FROSTI, a full-scale prototype for controlling laser wavefronts at extreme power levels inside the Laser Interferometer Gravitational-Wave Observatory, or LIGO.

LIGO is an observatory that detects —ripples in spacetime caused by massive accelerating objects like merging black holes. It was the first to confirm their existence, supporting Einstein’s Theory of Relativity. LIGO uses two 4-km-long laser interferometers in Washington and Louisiana to capture these signals, opening a new window into the universe and deepening our understanding of , cosmology, and extreme states of matter.

LIGO’s mirrors are among the most precise and carefully engineered components of the observatory. Each mirror is 34 cm in diameter and 20 cm thick and weighs about 40 kg. The mirrors must remain perfectly still to detect distortions in spacetime smaller than 1/1,000th the diameter of a proton. Even the smallest vibration or environmental disturbance can overwhelm the gravitational wave signal.

New perspectives on light-matter interaction: How virtual charges influence material responses

Understanding what happens inside a material when it is hit by ultrashort light pulses is one of the great challenges of matter physics and modern photonics. A new study published in Nature Photonics and led by Politecnico di Milano reveals a hitherto neglected but essential aspect, precisely the contribution of virtual charges, charge carriers that exist only during interaction with light, but which profoundly influence the material’s response.

The research, conducted in partnership with the University of Tsukuba, the Max Planck Institute for the Structure and Dynamics of Matter, and the Institute of Photonics and Nanotechnology (CNR-IFN) investigated the behavior of monocrystalline diamonds subjected to lasting a few attoseconds (billionths of a billionth of a second), using an advanced technique called attosecond-scale transient reflection spectroscopy.

By comparing with state-of-the-art , researchers were able to isolate the effect of so-called virtual vertical transitions between the electronic bands of the material. Such an outcome changes the perspective on how light interacts with solids, even in hitherto attributed only to the movement of actual charges.

Key enzyme for high-value natural sweetener production identified and characterized

Steviol glycosides, natural sweeteners extracted from Stevia rebaudiana, are widely used as sucrose substitutes due to their high sweetness and low caloric value. Among them, Rebaudioside M (Reb M) is regarded as a next-generation, high-value steviol glycoside product because of its intense sweetness and superior taste profile. However, the natural abundance of Reb M in Stevia is extremely low.

Efficient biosynthetic methods are needed to meet market demand. Until now, the key enzyme catalyzing the conversion of Rebaudioside D (Reb D) to Reb M in the has not been identified, and it is generally assumed to be UGT76G1. However, UGT76G1 exhibits strict regioselectivity for the C13 position of steviol glycosides, while its at the C19 position is very weak.

In a study published in the Proceedings of the National Academy of Sciences on September 17, a team led by Prof. Yin Heng from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences identified the key glycosyltransferase that catalyzes the conversion of Reb D to Reb M, and revealed the underlying its substrate regioselectivity.

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