All posts tagged: electric fields

Excitons Let Scientists Reshape Quantum Materials With Less Light

Excitons Let Scientists Reshape Quantum Materials With Less Light

Published by Jenni Sidey

Light can do more than illuminate a material. In some cases, it can temporarily change how electrons move through it. That possibility sits at the heart of Floquet engineering, a young area of condensed-matter physics that aims to create new electronic behavior on demand. “Excitons couple much stronger to the material than photons due to the strong Coulomb interaction, particularly in 2D materials,” says Professor Keshav Dani from the Femtosecond Spectroscopy Unit at OIST, “and they can thus achieve strong Floquet effects while avoiding the challenges posed by light. With this, we have a new potential pathway to the exotic future quantum devices and materials that Floquet engineering promises.” The time- and angle-resolved photoemission spectroscopy (TR-ARPES) setup at OIST, here with study co-first author Xing Zhu, PhD student in the Femtosecond Spectroscopy Unit. (CREDIT: Bogna Baliszewska (OIST)) Turning a rhythm into new electronic behavior “Floquet engineering starts with a basic idea: a repeating push can create a bigger, more complex response. A swing rises higher when pushes come at the right rhythm. In quantum materials, …

Scientists finally explain how lightning forms inside storm clouds

Scientists finally explain how lightning forms inside storm clouds

Published by Jenni Sidey

For as long as people have watched storms roll across the sky, lightning has inspired awe and fear. You can see the flash and hear the thunder, but the true beginning of a lightning bolt has remained hidden deep inside clouds. Scientists have known for decades how lightning travels once it forms, but the exact trigger inside a thundercloud stayed uncertain. A new study now offers the clearest explanation yet for how lightning truly begins. The research was led by Victor Pasko, a professor of electrical engineering in the Penn State School of Electrical Engineering and Computer Science. His team combined advanced mathematical modeling with real-world observations to explain a powerful chain reaction inside storm clouds. This reaction links strong electric fields, high-energy electrons, X-rays, and gamma rays into a single process that starts lightning. “Our findings provide the first precise, quantitative explanation for how lightning initiates in nature,” Pasko said. “It connects the dots between X-rays, electric fields and the physics of electron avalanches.” This work does more than solve a scientific puzzle. It …