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Category: particle physics – Page 25

New microscope reveals previously hidden differences in photosynthetic light-harvesting antennae

How do photosynthetic organisms harvest light so efficiently? To help answer this question, researchers have developed an ultrafast transient absorption microscope with sensitivity approaching the single-molecule level.

Plants and photosynthetic bacteria have a wide variety of light-harvesting antennae in which pigment molecules are precisely arranged to utilize light energy efficiently. However, these molecular arrangements are not perfectly uniform and vary from particle to particle because of conformational distortions and fluctuations. Such structural variations are considered to perturb excited states and energy transfer processes triggered by light absorption. Because these early excitation dynamics initiate a cascade of photosynthetic photochemical reactions, understanding the effects of such fluctuations and heterogeneities is essential for revealing how phototrophic organisms maintain efficient and stable photosynthesis.

To analyze these fluctuations and heterogeneities, single-molecule fluorescence spectroscopy has been widely utilized. However, the fluorescence-based approach faces fundamental challenges in observing ultrafast and multistep processes, as well as non-fluorescent dark states and radical species.

Investigating the disordered heart of glass

Recent research led by the University of Trento reveals that fundamental atomic vibrations remain unchanged also in ultra-stable glasses. This discovery advances the decade-long debate on the physics of disorder and opens the way to new applications, from electronics to pharmaceuticals. The research work was carried out by the Department of Physics in collaboration with other European research institutions and published in Physical Review X.

We are used to thinking of glass as a fragile and common material, but glass is still one of the greatest enigmas for physics. In crystals, atoms are arranged in geometric order, while chaos reigns in glass. This disorder generates unique properties, especially near absolute zero, where the glass behaves very differently from crystals. A study conducted by the Department of Physics of the University of Trento in collaboration with the European Synchrotron Radiation Facility (ESRF) in Grenoble and other European research centers sheds new light on this mystery.

The working group analyzed the so-called ultra-stable glasses, which are produced with advanced techniques that make them perfect candidates for the title of “ideal glass.” The first author of the paper is Irene Festi, who worked on the project for her Ph.D. thesis at the Department of Physics of the University of Trento. Giacomo Baldi, professor of Experimental Physics of Matter and head of the Laboratory of Structure and Dynamics of Complex Systems at the same Department of UniTrento, is the scientific coordinator of the study.

A New Way to View Shockwaves Could Boost Fusion Research

At the heart of our sun, fusion is unfolding. As hydrogen atoms merge to form helium, they emit energy, producing the heat and light that reach us here on Earth. Inspired by our nearby star, researchers want to create fusion closer to home. If they can crack the engineering challenges underlying the process, they would create an abundant new source of power to eclipse all others.

One of those challenges is understanding what happens at the smallest scales during fusion reactions so that researchers can better control the process. In one of the two main kinds of fusion, inertial confinement fusion (ICF), researchers bombard a fuel-filled capsule with lasers to create shockwaves and heat and compress the target, kicking off fusion. That means lots of complex interactions that scientists haven’t been able to get a good look at — until now.

A team of researchers used a new approach at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) to watch how a shockwave moved through water in extreme detail, making a never-before-seen movie of how the material compressed and how the electric and magnetic fields evolved. They were intrigued to discover that water provided a good analog for what happens when a laser strikes an ICF target. Scientists captured the process using both X-rays and an electron beam, a unique dual view known as “multi-messenger” imaging.

Gravitational waves may have created dark matter in the early universe

In the chaotic first moments after the Big Bang, ripples in spacetime may have done more than just echo through the cosmos—they could have helped create dark matter itself. New research suggests that faint, ancient gravitational waves might have transformed into particles that eventually became the invisible substance shaping galaxies today.

Raman Spectroscopy Could Reveal if Enceladus is Habitable

Raman spectroscopy can be used to identify minerals in Enceladus’s plumes to help determine if its subsurface ocean could support life. [ https://www.labroots.com/trending/space/30495/raman-spectros…abitable-2](https://www.labroots.com/trending/space/30495/raman-spectros…abitable-2)

Is Saturn’s ocean moon Enceladus habitable? This is what a recent study published in The Planetary Science Journal hopes to address as a team of scientists investigated the likelihood of Enceladus hosting the necessary ingredients for life as we know it. This study has the potential to help scientists develop new methods for finding life beyond Earth, even life as we don’t know it.

For the study, the researchers examined whether Raman spectroscopy, which is a common chemical analysis method in planetary science, could be used to analyze particles emitted from Enceladus’ plumes. These plumes, which originate from Enceladus’ south polar region, are responsible for discharging pieces of the moon’s interior ocean, including water vapor and other molecules. To accomplish this, the researchers used a vacuum chamber to simulate conditions on Enceladus and froze salt water at pH levels of 9 and 11. They then analyzed the salts using Raman spectroscopy to ascertain if it could identify particles within the water and determine which pH level they originated from.

In the end, the researchers discovered that the instrument could differentiate between the two pH levels while identifying sodium bicarbonate (baking soda) and sodium carbonate (washing soda) in both pH levels while identifying only sodium bicarbonate (baking soda) in pH 11. The researchers note these findings demonstrate the potential for using a spacecraft-mounted Raman spectrometer for future missions to Enceladus and other icy worlds with the goal of identifying the necessary ingredients for life as we know it.

Atomic Clocks: Exquisite Sensors for More Than Just Time

Atomic clocks use the quantum energy levels of atoms to tell time more accurately and precisely than any other kind of clock. (Learn more about how atomic clocks work.)

But atomic clocks can be used for more than timekeeping. They can serve as quantum sensors. Indeed, companies already use portable atomic clocks to detect oil deposits under the ocean. As these clocks become even more accurate and precise, their sensing capabilities become increasingly powerful.

To understand how atomic clocks work as sensors, we need to know a bit about Einstein’s theory of general relativity. Relativity tells us that time ticks more slowly in stronger gravity. Here on Earth, for example, a clock ticks slightly more slowly at sea level than it would on the top of a mountain, because gravity is stronger at sea level. For similar reasons, clocks in space speed up relative to those on Earth.

Room-temperature vibrations could transform how industry makes graphene

Researchers have demonstrated a new technique for creating 2D materials that runs at room temperature and increases production rates tenfold over current methods, without using toxic solvents. Scientists led by Dr. Jason Stafford from the Department of Mechanical Engineering demonstrated the method can produce nanosheets of conductors, semiconductors and insulators, which are the building blocks of all digital devices and technologies produced today. The research is published in the journal Small.

Dr. Stafford said, “Our work shows a new way of making 2D materials that overcomes the production capacity issues of current methods, while simultaneously embedding sustainable manufacturing practices.”

2D materials are ultra-thin materials that consist of a few layers of atoms. They have unique electronic, thermal, and mechanical properties that differ significantly from their 3D counterparts, and are ideal components for next-generation electronics, energy and sensor technologies.

Machine learning offers faster, more reliable analysis of Fermi surfaces in search of spintronic materials

The search for next-generation electronic materials often starts with studying the Fermi surface, which serves as a map of a material’s electronic structure. Its shape varies with crystal structure, composition, and electronic band arrangement, directly impacting properties such as carrier density, magnetic behavior, and spin polarization. This makes it a crucial tool for understanding and engineering new materials.

The Fermi surface of a material is determined experimentally using techniques such as angle-resolved photoemission spectroscopy (ARPES). However, interpreting ARPES data requires specialized expertise, and the measurements themselves are often susceptible to noise. As experiments produce larger amounts of data, carefully reviewing every image by hand becomes time-consuming and inefficient.

Single X-ray photons reveal hidden light-matter interactions in 50-nanometer double slits

A rainbow reveals with colors what otherwise remains hidden: light is “refracted” by transparent matter, in this case water droplets. This same physical effect underlies many everyday technologies, like LCD screens and broadband connections based on fiber-optic cables. Light refraction is caused by an interaction between light and the atoms of matter. This brings the light waves slightly out of sync, so to speak. “X-ray light” is “refracted,” too. But the effect is difficult to measure here.

A miniature device now offers a novel approach: Researchers from the Universities of Göttingen and Hamburg, together with partners, have built the world’s smallest X-ray interferometer, to their knowledge. It has enabled them to precisely measure, for the first time, the refraction of X-rays confined to a few nanometers, and to deduce how they interact with atomic nuclei. The study was published in the journal Nature Photonics.

The new X-ray interferometer is based on the famous double-slit experiment, which Nobel laureate Richard Feynman said “has in it the heart of quantum mechanics.”

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