Interacting polarons

Potassium atoms ( yellow ) surrounded by lithium atoms ( blue ) form polarons that interact with each other. IQOQI Innsbruck/Harald Ritsch - In physics, the complex processes in solids are often described in terms of quasiparticles. In ultracold quantum gases, these quasiparticles can be reproduced and studied. Now, for the first time, Innsbruck scientists led by Rudolf Grimm have been able to observe in experiments how Fermi polarons - a special type of quasiparticle - can interact with each other. They report on this in the journal Nature Physics . When an electron moves through a solid, it generates a polarization in its environment due to its electric charge. In his theoretical considerations, the Russian physicist Lev Landau extended the description of such particles to include their interaction with the environment and spoke of quasiparticles.