A study has found that the cortex acts like a ‘memory machine’, encoding new experiences and predicting the near future, helping to differentiate between novel and old information.
Terahertz radiation (THz), electromagnetic radiation with frequencies ranging from 0.1 and 10 THz, is central to the functioning of various technologies, including imaging, sensing and spectroscopy tools. While THz radiation waves have been manipulated in different ways over the past decades, controlling their direction in air has so far remained a challenge.
Researchers at Ecole Polytechnique (CNRS) at Institut Polytechnique de Paris recently demonstrated the steering of laser-produced THz radiation in air, using a recently introduced technique dubbed “flying focus.” Their paper, published in Physical Review Letters, could open new possibilities for the manipulation of THz electromagnetic waves, which could in turn be leveraged to develop new technologies.
“My group has been working on the generation of THz radiation by laser-induced filaments in air for almost 20 years,” Aurélien Houard, senior author of the paper, told Phys.org. “A major advantage of these filaments is that they can be generated at a large distance from the laser in the atmosphere. However, the THz emission remained confined close to the laser axis, which is not convenient for remote detection.”
An international team of astronomers has investigated a newly detected Type II supernova designated SN 2024jlf. The new study, detailed in a paper published Jan. 30 on the arXiv pre-print server, yields important information regarding the evolution of this supernova and the nature of its progenitor.
Type II supernovae (SNe) are the results of rapid collapse and violent explosion of massive stars (with masses above 8.0 solar masses). They are distinguished from other SNe by the presence of hydrogen in their spectra.
Based on the shape of their light curves, they are usually divided into Type IIL and Type IIP. Type IIL SNe show a steady (linear) decline after the explosion, while Type IIP exhibit a period of slower decline (a plateau) that is followed by a normal decay.
Data security on the internet is under threat: in the future, quantum computers could decode even encrypted files sent over the internet in no time. Researchers worldwide are, therefore, experimenting with quantum networks that will enable a paradigm shift in the future when globally connected to form the quantum internet.
Such systems would be able to guarantee tap-proof communication through quantum mechanical phenomena such as superposition and entanglement, as well as cryptographic quantum protocols. However, the quantum internet is still in its infancy: high costs coupled with high energy consumption and a high level of complexity for the necessary technologies have prevented quantum networks from scaling easily.
Two researchers at the Institute of Photonics at the Leibniz University Hannover want to remedy this situation. Using frequency-bin coding, they have developed a novel method for entanglement-based quantum key distribution. This quantum mechanical encryption technique uses different light frequencies, i.e. colors, to encode the respective quantum states. The method increases security and resource efficiency.
Carnegie Mellon University’s Professor Curtis Meyer and his research colleagues explore an uncharted world inside protons and neutrons. For the first time, researchers have provided measurements describing a maximum boundary for a subatomic particle known as a hybrid meson in a journal paper published in Physical Review Letters. The measurements show scientists a path forward in a search for these elusive particles that provide a new look at the force that holds all matter together.
“The stage is set for future discoveries,” said Meyer, senior associate dean for CMU’s Mellon College of Science and the Otto Stern Professor of Physics. “We’re at an exciting phase where we’re able to analyze a great deal of data. This paper is the first to address one of the experiment’s foundational questions.”
Applying a symmetry property of the strong force, the team set the upper limit on the photoproduction cross sections of a hybrid meson known as the spin-exotic π1 (1600).
The commonplace phenomenon of liquid drops falling from a surface is—perhaps surprisingly—not yet fully understood by scientists. Understanding the complex interactions between the forces involved here would be helpful in industry, where structured packings in cooling towers must be designed to encourage droplet formation in fluid flow but coatings mixed to maintain a pristine, smooth surface.
Furthermore, the design of meshes used to harvest clean water from fog or dew, where this is limited, relies on an understanding of how the water condenses on the fibers and drops into collection tanks.
Atefeh Pour Karimi, a Ph.D. student at the Institute of Heat and Mass Transfer, Aachen University, Germany, and her supervisors and collaborators have analyzed the dynamics of this type of flow in detail and published their findings in The European Physical Journal Special Topics.
Laser diodes are semiconductors that generate light and amplify it using repeated reflection or “optical feedback.” Once the light has achieved desirable optical gain, laser diodes release it as powerful laser beams.
Photonic crystal surface-emitting lasers (PCSELs) are advanced laser diodes where the optical gain is typically distributed laterally to the propagating light within a photonic crystal (PC) structure. They differ from traditional lasers by separating gain, feedback, and emission functions, offering scalable single-mode power and innovative designs. This leads to enhanced performance and new application possibilities.
In a paper that was published in the IEEE Journal of Selected Topics in Quantum Electronics on 20 November 2024, researchers have developed a method to numerically simulate the interaction of light waves within PCSELs.
A recent study in an animal model provides direct evidence for the role of the vagus nerve in gut microbiome-brain communication, addressing a critical gap in the field.
The research—led by Kelly G. Jameson, as a Ph.D. student in the Hsiao Lab at UCLA—demonstrates a clear causal relationship between gut microbiota and vagal nerve activity. The work is published in the journal iScience.
While the vagus nerve has long been thought to facilitate communication between the gut microbiome—the community of microorganisms living in the intestines—and the brain, direct evidence for this process has been limited. Researchers led by Jameson observed that mice raised without any gut bacteria, known as germ-free mice, exhibited significantly lower activity in their vagus nerve compared to mice with a normal gut microbiome. Notably, when these germ-free mice were introduced to gut bacteria from normal mice, their vagal nerve activity increased to normal levels.
Researchers from SANKEN (The Institute of Scientific and Industrial Research) at Osaka University have discovered that temperature-controlled conductive networks in vanadium dioxide significantly improve the sensitivity of silicon devices to terahertz.
Terahertz radiation refers to the electromagnetic waves that occupy the frequency range between microwaves and infrared light, typically from about 0.1 to 10 terahertz (THz). This region of the electromagnetic spectrum is notable for its potential applications across a wide variety of fields, including imaging, telecommunications, and spectroscopy. Terahertz waves can penetrate non-conducting materials such as clothing, paper, and wood, making them particularly useful for security screening and non-destructive testing. In spectroscopy, they can be used to study the molecular composition of substances, as many molecules exhibit unique absorption signatures in the terahertz range.
A team of scientists has unlocked a new frontier in quantum imaging, using a nanoscale.
The term “nanoscale” refers to dimensions that are measured in nanometers (nm), with one nanometer equaling one-billionth of a meter. This scale encompasses sizes from approximately 1 to 100 nanometers, where unique physical, chemical, and biological properties emerge that are not present in bulk materials. At the nanoscale, materials exhibit phenomena such as quantum effects and increased surface area to volume ratios, which can significantly alter their optical, electrical, and magnetic behaviors. These characteristics make nanoscale materials highly valuable for a wide range of applications, including electronics, medicine, and materials science.