Hydrogen, the most abundant element in the cosmos, plays a vital role in shaping celestial bodies, supporting life on Earth, and advancing clean energy solutions. Despite its seemingly simple composition, hydrogen's characteristics remain enigmatic, captivating generations of scientists in the fields of physics and chemistry.
In a groundbreaking revelation, a collaborative team from Christian-Albrechts-Universität zu Kiel (CAU) and Helmholtz-Zentrum Dresden-Rossendorf (HZDR) has unearthed a remarkable phenomenon: hydrogen exhibits an unexpected “roton-like behavior” when subjected to intense pressure. This distinctive behavior influences the scattering of X-ray light in a novel manner.
Remarkably, X-ray photons interact with electrons, transferring energy whose magnitude escalates with the momentum conveyed. Intriguingly, in dense hydrogen, energy can decrease as momentum transfer intensifies. The findings, featured in the latest edition of Physical Review Research and hailed as Editors' Suggestion, unveil parallels with distinct systems like exotic Bose fluids operating near absolute zero. These fluids, renowned for superfluidity and quantum phenomena, challenge classical statistical mechanics.
Professor Michael Bonitz, leader of CAU's Institute for Theoretical Physics and Astrophysics, attributes this phenomenon to the behavior of unbound electrons, a key departure from atom-bound counterparts. Dr. Tobias Dornheim of HZDR further elucidates that under X-ray irradiation, electrons surprisingly draw close and even form pairs despite inherent repulsion.
Leveraging advanced computer simulations, the research team has meticulously delineated conditions for observable roton behavior. The onus now rests upon experimental physicists to empirically validate these predictions, paving the way for deeper insights into hydrogen's enigmatic nature.
Source: Kiel University