Ultrafast Entropy Production by Magnons

Ultrafast demagnetization processes can be observed in THz pump and probe experiments. The exact microscopic behavior of the magnons involved is described by a Landau-Lifshitz- Gilbert equation that includes stochastic noise, damping and nutation terms. From this equation of motion, thermodynamic quantities are determined via a path integral formalism. The resulting entropy production is specified for ferro- and anti-ferromagnets, and experimentally measurable quantities are predicted assuming time-resolved magneto-optical Kerr-effect.

We acknowledge support from the Swedish Research Council (VR starting Grant No. 2022-03350) and Chalmers University of Technology, via the department of Physics, the area of advance Materials, and the area of advance Nano.