SmallTalks "Can electrons flow like water?"

Abstract 

In classical physics, electrons are imagined as pinballs, traveling through a conductor and scattering off defects, giving rise to resistance. This offers a quasiparticle picture of electrical transport. But what if electrons moved collectively, more like a fluid than bouncing particles?

For certain quantum materials, such as YBa₂Cu₃O_7−δ (YBCO), the quasiparticle picture breaks down. Recent theories suggest that under certain conditions, electrons may exhibit hydrodynamic behavior, flowing like water rather than bouncing like pinballs. To explore this regime, we fabricated nanometric-sized Tesla valves on YBCO, a geometry originally designed to favor directional flow in fluids. In electrical transport, this structure aims to test direction-dependent resistance.

In this talk, we present resistance measurements and discuss competing effects that may mask hydrodynamic transport signatures. Disentangling these contributions is key for identifying the conditions to observe hydrodynamic behavior—and for understanding the true nature of electron transport in these quantum materials.