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Portable UV spectrometer can detect air pollutants across 2.5 km with high precision

Birgitta Schultze-Bernhardt and her team at the Institute of Experimental Physics at Graz University of Technology (TU Graz) have developed a new type of UV dual-comb spectrometer that detects gaseous air pollutants with unrivaled accuracy and sensitivity. Using ultraviolet double laser light, the device measures the concentration of harmful gases such as formaldehyde within half a second.

Thanks to its compact design and a measuring range of up to two and a half kilometers, the spectrometer is not only suitable for laboratory analyses, but also for mobile measurements in cities, industrial areas and agricultural regions.

The work is published in the journal PhotoniX.

Chip-scale ‘acoustic atom’ controls sound waves to imitate atomic energy levels and advance computing

For every action, there is an equal and opposite reaction. What goes up must come down. Physical laws like these govern all of the natural world—except for the tiny internal components of today’s microprocessors, which operate according to the unique and complicated rules of quantum physics.

As the microprocessors that power computers, medical equipment, sensors, and more continue to shrink in size, engineers face challenges controlling quantum-scale systems. But in a step forward for the technology, researchers at Virginia Tech have developed an “acoustic atom”—a chip-scale device that traps and controls sound waves in ways that mimic the behavior of real atoms. Long term, these advances could influence technologies connected to quantum artificial intelligence (AI), telecommunication, medical imaging, GPS, and more.

The research is published in Physical Review Letters by Linbo Shao, assistant professor in Virginia Tech’s Bradley Department of Electrical and Computer Engineering, along with colleagues at the university’s Center for Power Electronic Systems, Department of Physics, and Center for Quantum Information Science and Engineering and the Oak Ridge National Laboratory.

Ultrafast laser shrinks to chip scale, potentially lowering costs for diagnostics and atomic clocks

Ultrafast lasers emit pulses lasting only a few hundred femtoseconds (quadrillionths of a second). These flashes of light power applications from precision micromachining to eye surgery to optical frequency combs, the Nobel Prize-winning technology behind today’s most precise optical atomic clocks. Yet despite more than two decades of effort, ultrafast lasers have largely remained bulky, expensive systems confined to optical tables.

Now a team led by Professor Tobias J. Kippenberg at EPFL has brought them onto a photonic chip. Publishing in Nature, the researchers report the first integrated ultrafast laser to rival tabletop femtosecond lasers, delivering 1.05 nanojoules in pulses as short as 147 femtoseconds.

Photonic chips guide and process light in microscopic channels called waveguides patterned on a wafer, similar to how electronic microchips route electricity. Already widely used in telecommunications, photonic chips have miniaturized complex functions that once required much larger systems.

Temperature gaps help sneeze clouds stay denser and travel farther, experiments show

When a person coughs or sneezes, they expel a cloud of microscopic particles capable of carrying viruses and bacteria that act as vectors for respiratory diseases such as flu, COVID-19 or tuberculosis. Understanding how these aerosols disperse in the air is crucial for minimizing the transmission of pathogens in indoor spaces, but their dynamics are complex and depend on many factors: the force of the exhalation, the morphology of the respiratory system, the characteristics of the space, etc. Now, a new study led by researchers from the Universitat Rovira i Virgili has shown that temperature also plays an important role.

Their findings, published in Physics of Fluids, indicate that the difference between the temperature of exhaled air and that of the ambient air causes the cloud of particles to remain more concentrated and travel farther. The greater this difference, the more noticeable the effects are.

The research continues a line of work initiated by the URV’s ECoMMFiT research group, which developed a simulator capable of reproducing coughs and sneezes to study how respiratory aerosols disperse. As a result of that study, the team demonstrated that the nasal cavity significantly alters the trajectory of expelled particles. Now, the researchers have incorporated a new factor into the analysis: temperature.

‘Don’t scare the cat!’ Engineers find smarter way to measure quantum systems

UNSW Sydney engineers have riffed on the famous Schrödinger’s cat analogy to demonstrate a more efficient way to eliminate errors in quantum computing.

“Imagine you’re trying to find your cat hiding in one of eight identical cardboard boxes, in a dark and noisy room,” says UNSW Scientia Professor Andrea Morello.

“You are not allowed to enter the room—opening the door may kill the cat. What is the optimal strategy to find out where it’s hiding? Our team of quantum researchers have found an answer to this problem, and it might be an important milestone on the road to building a quantum computer.”

Violating the 3rd law of black hole mechanics in vacuum gravity

Black holes, regions in space where gravity is so strong that nothing can escape, have been widely studied over the past decades, due to their unique and intriguing properties. Einstein’s theory of general relativity predicts that black holes obey a set of rules, known as the laws of black hole mechanics. These rules somewhat resemble the laws of thermodynamics, which delineate how energy, heat, and entropy behave in our universe.

The 3rd law of black hole mechanics states that an extremal black hole, or in other words, a black hole that is spinning or charged to its absolute theoretical limit, cannot realistically form in a finite amount of time.

Extremal black holes are predicted to have a surface gravity of zero, thus they do not emit standard Hawking radiation and would not evaporate in a vacuum. This specific characteristic of extremal black holes is known as “zero temperature.”

Solar sails edge closer to reality, but interstellar travel is another story

From planetary rovers and asteroid sample return missions to the recent Artemis II flight above the far side of the moon, we are seemingly good at doing space. But our achievements still do not match many of our space dreams, science fiction or otherwise.

One of the long-mentioned ways of achieving some of our ambitions for exploring the cosmos is space sails. These are large, lightweight structures that use the radiation pressure of sunlight to move. But apart from a handful of demonstration missions, including Japan’s IKAROS spacecraft, the technology has still not really gotten off the ground.

Deep-Earth seismic anomalies may be explained by newly discovered manganese compound

Scientists know that manganese, in its various oxide forms, plays a significant role in Earth’s geochemical cycles. However, the exact forms of manganese, their abundance and the mechanisms behind these cycles that occur in Earth’s deep, high-pressure interior are not well understood. But, a recent study, published in Physical Review B, reports on a newly discovered manganese rich compound that might help shed light on manganese’s behavior in Earth’s interior and explain why seismic waves slow down in certain regions.

While Earth’s mantle mostly consists of oxygen, magnesium, silicon, and iron, other elements, like manganese, also play an important role. Manganese oxides, such as MnO, Mn3O4, Mn2O3, MnO2, are known to exist in Earth’s interior and have been studied in the context of their stability in the high-pressure conditions of Earth’s mantle, but researchers think there may be additional manganese oxides involved.

These compounds have the ability to react with other compounds (and oxidize) depending on the surrounding pressure and temperature. They often act as powerful, pressure-sensitive redox agents, actively participating in deep-Earth geochemical cycling by reacting with and oxidizing subducted iron-bearing minerals.

Distant blazar OP 313 emits very high-energy gamma rays above 100 GeV

An international team of astronomers have employed one of the Large-Sized Telescopes (LSTs) at the Cherenkov Telescope Array Observatory (CTAO) to observe a distant blazar known as OP 313. Results of the observational campaign, published May 26 on the arXiv preprint server, shed more light on the behavior and nature of this object.

Blazars are extremely compact quasi-stellar objects (quasars) associated with supermassive black holes (SMBHs) at the centers of active, giant elliptical galaxies. They are the most luminous and extreme subclass of active galactic nuclei (AGNs). The characteristic features of blazars are highly collimated relativistic jets oriented very close to our line of sight.

Based on their optical emission properties, astronomers generally divide blazars into two classes: flat-spectrum radio quasars (FSRQs) that feature prominent and broad optical emission lines, and BL Lacertae objects (BL Lacs), which do not.

Open-source software unlocks rapid DNA structure generation and analysis in one workflow

Computational chemists at the University of Amsterdam’s Van ‘t Hoff Institute for Molecular Sciences have developed a comprehensive software suite to create accurate models of DNA in biomolecular assemblies. Called MDNA, the user-friendly molecular modeling toolkit helps biochemists, molecular biologists, bioinformaticians, and biophysicists to visualize and analyze DNA structures and perform accurate simulations.

The development of the MDNA suite, led by associate professor Jocelyne Vreede, has been presented in a paper in Nucleic Acids Research.

The software is open-source and publicly available through Figshare and Github. It is easily accessible, providing inspiration to any scientist with an interest in DNA. It has been thoroughly tested by students in mathematics, chemistry and biology, some of whom had hardly any programming experience.

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