The violent breaking of waves is both visually spectacular and meteorologically impactful.
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The art of good conversation may involve a little pink noise
Most of us like a good old chat with friends, colleagues, neighbors or acquaintances. But what can turn a really good chat into a great one? Sure, conversation topics matter, but scientists have found underlying patterns that may explain our best interactions.
The question has long vexed scientists. Previous studies have mostly focused on how closely people’s words and ideas match, rather than how chats flow and shift from one moment to the next.
But researchers Kathryn O’Nell, Emily Finn and Kiara L. Sanchez at Dartmouth College in the United States took a different approach.
Gatineau Park foliage reveals local Cold War nuclear testing legacy
For more than six decades, local scientists have collected sugar maple leaves from Gatineau Park to measure their radiocarbon levels, creating the longest continuous record of its kind. Now, a study of those leaves led by the André E. Lalonde National Facility for Accelerator Mass Spectrometry (AEL-AMS) located at the University of Ottawa shows that the effects of Cold War–era nuclear weapons testing have only recently disappeared from the local biosphere. The study, titled “Stored carbohydrates buffer Bomb and Suess radiocarbon effects in maple leaves across a 65-year Ottawa region record,” was published in Scientific Reports.
The Geological Survey of Canada began collecting maple leaves in Gatineau Park in 1961, taking samples once a month during each growing season. Its scientists analyzed the leaves until the agency’s radiocarbon laboratory closed in 2004. The AEL-AMS later took over the analyses and extended the record through 2025, adding 59 annual and seasonal measurements. The collection is ongoing, though leaves gathered in September 2026 are not included in the current study.
“These leaves are a 65-year diary of the atmosphere,” explains Dr. Leonard Wassenaar, executive director of the André E. Lalonde National Facility for Accelerator Mass Spectrometry (AMS) at the University of Ottawa. “It took more than 65 years for the extra radiocarbon from weapons testing to disappear from the Ottawa-area biosphere. The effects were still with us decades after the last test.”
New perovskite system extends room-temperature spin polarization via successive quantum wells
A research team led by Lu Haipeng, a professor in the Department of Chemistry at The Hong Kong University of Science and Technology (HKUST), has achieved a breakthrough in preserving spin information for optoelectronic technologies. The team has developed a perovskite chiral multiple quantum-well system that maintains spin polarization approximately 300 times longer at room temperature. The study opens new possibilities for future quantum technologies and next-generation spin-based applications. The study was published in the journal Nature Photonics.
Semiconductors underpin modern optoelectronic devices, yet the industry continues to face challenges in improving processing speed while reducing energy consumption. To overcome these limitations, researchers are exploring new approaches, particularly spin-based technologies. However, manipulating spin states at room temperature remains extremely difficult due to the rapid spin decoherence process.
To address these challenges, the HKUST research team developed a novel perovskite chiral multiple quantum-well system that enables an efficient “spin cascade” process. Using a two-step seed-assisted crystallization approach, the team constructed well-oriented quantum wells with varying widths and continuous intrinsic chirality across two-dimensional (n = 1), quasi-two-dimensional (n = 2, 3, 4, …) and three-dimensional (n = ∞) perovskite phases.
Light-pulse pairs reveal the femtosecond decay of an inner-shell hole in xenon atoms
Researchers at the UVSOR Synchrotron Facility (Institute for Molecular Science, Japan) and partner institutions have observed the decay of a xenon 4D core hole, an inner-shell vacancy, directly in the time domain. They used pairs of phase-coherent extreme ultraviolet pulses from a synchrotron to make the photoelectron wave packets they released interfere. The contrast of the interference fringes decreased over a few femtoseconds as the delay between the pulses increased. A model using literature core-hole lifetimes of about 6 femtoseconds reproduced this rapid decay of the fringe contrast. The study is published in the journal Physical Review A.
Auger decay is an ultrafast process. A valence electron fills an inner-shell vacancy, and another electron is ejected. It dominates the decay of the xenon 4D hole. Until the mid-2000s, experiments mostly inferred such dynamics from the spectral widths of photoelectron lines. Attosecond streaking later made time-domain observation possible. While attosecond streaking has been widely employed for time-domain observations of Auger processes, the research team has introduced an alternative approach based on coherent pulse pairs. The present work extends the photoelectron wave-packet interferometry to core holes created by photoionization.
At beamline BL1U of the UVSOR-III synchrotron, two undulators in tandem, separated by a phase-shifter magnet, emitted phase-coherent pulse pairs. The photon energy was 93.4 eV, with a bandwidth of about 3%. The phase-shifter magnet set the delay between pulses with attosecond resolution. The pulses ionized xenon 4D electrons, and a hemispherical analyzer recorded photoelectron spectra as a function of delay. Helium, which has no comparable decay, served as a reference. Its fringe contrast revealed the instrument’s own contrast loss.
Light reflecting within thin films can masquerade as molecular signals in perovskite solar materials
An infrared signal thought to reveal how molecules in perovskite solar materials respond to light-generated charges can arise largely from the way light travels through the thin film itself, a new theoretical study shows. Jun Nishida, assistant professor at the Institute for Molecular Science (IMS), Japan, found that light-generated charges alter how infrared light is reflected and transmitted within the film layers, producing sharp features that resemble changes in molecular vibrations even when the vibrations themselves are unaltered.
Published in The Journal of Chemical Physics and selected as an Editor’s Pick, the study names this mechanism carrier-induced photonic resonance (CIPR) and shows that it must be distinguished from genuine molecular responses when interpreting such measurements.
Barium titanate’s optical properties emerge more clearly after decades of widely varying measurements
A KAIST-led research team has characterized how light propagates through and is absorbed by barium titanate (BTO), a promising material for next-generation optical communication devices. By clarifying optical properties that had been difficult to determine because of the material’s complex internal structure, the study provides a foundation for designing these devices.
The research team led by professor Min Seok Jang of its School of Electrical Engineering had precisely characterized BTO’s refractive index and absorption properties across wavelengths ranging from the ultraviolet to the far-infrared. The study was conducted in collaboration with professor Harry A. Atwater’s team at the California Institute of Technology (Caltech), the Korea Research Institute of Standards and Science (KRISS) and U.S.-based J.A. Woollam Co. The work is published in ACS Photonics.
BTO’s refractive index changes when an electric field is applied. Its strong electro-optic response, known as the Pockels effect, makes it a promising material for optical modulators, which encode information from electrical signals onto light.
Atomic defects leave telltale optical fingerprints in quantum material
The tiny atomic defects so important for future quantum technologies can be difficult to spot. Fortunately, they leave behind some clues. The defects can alter how a material responds to light, producing a distinctive optical fingerprint that scientists can measure. The challenge is figuring out which fingerprints belong to which defects.
To that end, a University at Buffalo–led team has predicted the optical fingerprints of known atomic defects in hexagonal boron nitride (h-BN), a material with a honeycomb-like pattern of boron and nitrogen atoms. The team’s computer models simulated how different defects affect the intensity and polarization of the light produced when h-BN is hit with a laser.
Published in Nano Letters, these calculations could eventually help scientists distinguish between different types of defects in h-BN and determine which could be useful for emerging quantum technologies.
Quantum interference keeps two atoms bound despite enough energy to break apart
How can something remain intact when it should naturally break apart? This question has been addressed by researchers at RPTU. Their work has led to the experimental observation of an unusual quantum state in which two atoms remain bound together even though they possess enough energy to separate. The results have been published in the journal Nature Physics.
“What is remarkable is that the molecular state could decay from an energetic point of view, yet quantum interference suppresses this decay,” explains professor Artur Widera, head of the Individual Quantum Systems group at RPTU. “The wave nature of matter allows a state to remain bound even though we would normally expect it to decay.”
In simple terms, particles such as atoms do not behave solely like tiny objects. They also possess wavelike properties. When such waves overlap, they can either reinforce or cancel one another, a phenomenon physicists refer to as interference. As the new study demonstrates, it is precisely this effect that prevents two atoms from separating.
High-pressure setup unlocks detailed measurements of organized structures in turbulent flows
Turbulent flows are ubiquitous: they are found in clouds, in the ocean and even on other planets. Yet despite their chaotic nature, they also form large-scale structures that can be calculated and predicted. For example, while long streaks of clouds may appear orderly from the outside, their interiors are characterized by intense turbulence.
The high-pressure chamber at the Max Planck Institute for Dynamics and Self-Organization (MPI-DS), nicknamed the “submarine,” makes it possible to better understand the formation of these large-scale structures. Headed by research group leader Stephan Weiss and Director Eberhard Bodenschatz, the physicists have designed a special setup for such measurements. Their work is published in the Review of Scientific Instruments.
“The challenge is to generate flows with particularly strong turbulence, similar to those found in nature,” says Weiss. In their setup, the team uses a rectangular convection cell measuring 3.5 m long and 0.7 m high, whose temperature at the bottom and top can be regulated very precisely using heating and cooling plates. The experiments are conducted in a heavy gas (sulfur hexafluoride) at a pressure of up to 19 bar to replicate the large-scale turbulent flows found in nature on a smaller scale.