When heat flows like water
To understand how heat normally flows, you could study the second law of thermodynamics – or wrap your hands around a hot mug of coffee. Both tell us that heat tends to flow toward cooler regions. As a material’s thermal energy increases, its atoms vibrate, and quantum mechanics describes these vibrations as phonons: quasiparticles that transport heat. Normally, collisions between phonons cause heat to dissipate slowly. But in highly ordered, pure crystals, these collisions can result in a fluid-like, directional heat flow known as phonon hydrodynamics.
Researchers from the group of Theory and Simulation of Materials, led ...