Know What's Happening in Quantum

Electrons Stop Acting Like Particles—And Physics Still Works

Researchers at TU Wien showed that electrons in the heavy‑fermion compound CeRu₄Sn₆ cease to behave as well‑defined particles near absolute zero, yet the material still exhibits robust topological characteristics. By probing the quantum‑critical regime, they detected an anomalous Hall effect without any external magnetic field, confirming an emergent topological semimetal phase. The finding overturns the long‑standing assumption that particle‑like quasiparticles are required for topological states. The work, published in Nature Physics, combines low‑temperature experiments with theoretical modeling from Rice University.