GRK seminar:
Prof. Dr. Götz Uhrig

Concepts and applications in non-equilibrium physics

TU Dortmund

Non-equilibrium physics has become one of the thriving focal points in condensed matter physics. Pump-probe experiments are by now fairly common and further driving protocols attract more and more attention. We will discuss how periodic driving allows to cool a small quantum system by exploiting the commensurability of various oscillatory processes [1]. Interestingly, the Lindblad damping of a highly excited state is crucial here. Turning to ordered magnetic systems, it is common to describe their damping by Landau-Lifshitz-Gilbert equations. The question arises whether this phenomenological formalism is related to Lindblad damping. We will present such a conceptual link [2]. Finally, we explicity consider how one can switch magnetic order efficiently by electromagnetic pulses. How strong do the pulses have to be [3]? What is the influence of relaxation? These question are relevant for processing data in magnetic storage devices.

[1] Quantum coherence from commensurate driving with laser pulses and decay G.S. Uhrig; SciPost Phys. 8, 040 (2020)
[2] Landau-Lifshitz damping from Lindbladian dissipation in quantum magnets G.S. Uhrig; arXiv:2406.10613
[3] Exchange enhanced switching by alternating fields in quantum antiferromagnets A. Khudoyberdiev, G.S. Uhrig; Phys. Rev. B 111, 064408 (2025)

Venue: PHY 5.0.21