Inside a glass of water, electrons are constantly building and destroying tiny 'cages' for themselves every few quadrillionths of a second.
arXiv · March 16, 2026 · 2603.12537
Why it matters
While typically found in wires, electrons in water can get stuck in microscopic voids that act like the 'particle in a box' from physics textbooks. Researchers captured these 'hydrated electrons' in real-time, showing that their liquid cages are constantly and violently shifting shape on an ultrafast timescale.
From the abstract
Electron confinement within a small volume is intriguing as a realization of the particle-in-a-box system, which appears in every quantum mechanics textbook. While the electron confinement is readily imaginable in solid-state systems, it also occurs in liquids, where the local voids in the liquid serve as confining "boxes." Confinement within these flexible cavities in liquids is expected to differ fundamentally from that in solids. Here, we experimentally investigate the electrons confined in l