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Bose–Einstein condensation is a fundamental physical phenomenon demonstrating fascinating and application-important properties such as spontaneous coherence, superconductivity, and superfluidity. This phenomenon can be achieved either by a decrease in the temperature of ultracold atomic gases and cryogenic liquids or by an increase in the density of particles (quasiparticles). Spin wave quanta—magnons—are bosons, and thus they can form a Bose–Einstein condensate (BEC), which can be created by an external injection of these quasiparticles even at room temperature. In this talk, I will present the main ways of forming and observing magnon BEC in solid-state magnetic samples, outline its place in the spectrum of dipole-exchange magnons, describe the time dynamics of the overpopulated magnon gas and magnon condensate in real and momentum spaces, discuss the relation of this dynamics with magnon supercurrents, and touch upon the issue of temporal and spatial coherence of the magnon BEC.

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Dr. Oleksandr Serha (SFB1238/Kolloquium), Rheinland-Pfälzische Technische Universität
Seminar Room of the Institute of Physics II
Contact: Matteo Cacco (SFB1238/Kolloquium)