Researchers from Trinity College Dublin’s School of Engineering have built a powerful new machine that lets us watch precisely what happens when tiny particles—far smaller than a grain of sand—hit a surface at extremely high speeds. It’s the only machine like it in Europe, and it took over two years to design and build.
Scientists at the University of Stuttgart’s Institute of Aerodynamics and Gas Dynamics (IAG) have produced a novel dataset that will improve the development of turbulence models. With the help of the Hawk supercomputer at the High-Performance Computing Center Stuttgart (HLRS), investigators in the laboratory of Dr. Christoph Wenzel conducted a large-scale direct numerical simulation of a spatially evolving turbulent boundary layer.
Using more than 100 million CPU hours on Hawk, the simulation is unique in that it captures the onset of a canonical, fully-developed turbulent state in a single computational domain. The study also identified with unprecedented clarity an inflection point at which the outer region of the turbulent boundary layer begins to maintain a self-similar structure as it moves toward high Reynolds numbers. The results appear in a new paper published in the Journal of Fluid Mechanics.
“Our team’s goal is to understand unexplored parameter regimes in turbulent boundary layers,” said Jason Appelbaum, a Ph.D. candidate in the Wenzel Lab and leader of this research. “By running a large-scale simulation that fully resolves the entire development of turbulence from an early to an evolved state, we have generated the first reliable, full-resolution dataset for investigating how high-Reynolds-number effects emerge.”
Physicists at Bielefeld University and the Leibniz Institute for Solid State and Materials Research Dresden (IFW Dresden) have developed a method to control atomically thin semiconductors using ultrashort light pulses. The study, published in Nature Communications, could pave the way for components that are controlled at unprecedented speeds directly by light—ushering in a new generation of optoelectronic devices.
A research team led by TU Darmstadt has transformed a difficult problem in quantum physics into a much simpler version through innovative reformulation—without losing any important information. The scientists have thus developed a new method for better understanding and predicting difficult quantum mechanical systems. The study is published in Physical Review Letters.
This problem has long preoccupied quantum physics: How can systems consisting of many atoms, between which strong attractive forces act, be described mathematically? Already for about 10 particles, such systems are at the limits of current numerical methods.
It becomes particularly complicated when the atoms are exposed to an external force. However, this is the case in many experiments with cold atoms due to the way in which motion is restricted to one dimension, for example. Such systems of strongly interacting particles in one dimension were proposed in the 1960s and have since served as a reference problem in theoretical physics. So far, they have only been solved in a few special cases.
A new theory-guided framework could help scientists probe the properties of new semiconductors for next-generation microelectronic devices, or discover materials that boost the performance of quantum computers.
Research to develop new or better materials typically involves investigating properties that can be reliably measured with existing lab equipment, but this represents just a fraction of the properties that scientists could potentially probe in principle. Some properties remain effectively “invisible” because they are too difficult to capture directly with existing methods.
Take electron–phonon interaction—this property plays a critical role in a material’s electrical, thermal, optical, and superconducting properties, but directly capturing it using existing techniques is notoriously challenging.
An international team of scientists, including physicists from HSE MIEM, has demonstrated that when defects within a material are arranged in a specific pattern rather than randomly, superconductivity can occur at a higher temperature and extend throughout the entire material. This discovery could help develop superconductors that operate without the need for extreme cooling.
The study has been published in Physical Review B.
Superconductivity is a state in which electric current flows through a material without any energy loss. In conventional conductors, part of the energy is converted into heat, but in superconductors, this does not occur—current flows freely and does not weaken. Today, superconductors are used in applications such as MRI machines, where superconducting coils generate strong magnetic fields.
Neutrinos are among the most puzzling particles in the universe. Nearly massless and incredibly elusive, they rarely interact with anything, yet they play a deadly role in the life cycle of stars far larger than our sun. These subatomic particles exist in three known types—electron, muon, and tau—and despite decades of study, many of their behaviors remain poorly understood.
Because neutrinos interact so weakly, it is nearly impossible to make them collide under laboratory conditions. As a result, scientists still do not know whether they follow the interaction rules laid out by the standard model of particle physics or if they engage in theorized “secret” interactions exclusive to neutrinos.
In a new study, researchers with the Network for Neutrinos, Nuclear Astrophysics, and Symmetries (N3AS), including members from UC San Diego, have used theoretical models to demonstrate that massive stars in the final stages of their lives may naturally provide the perfect setting for studying these interactions.
