Dresden 2026 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 42: Other Transport Topics

TT 42.5: Talk

Wednesday, March 11, 2026, 10:30–10:45, HSZ/0105

Relaxation to persistent and oscillating currents in simply and doubly frustrated spin systems coupled to fermionic baths — •Nikodem Szpak¹, Gernot Schaller², Ralf Schützhold^{2, 3}, and Jürgen König¹ — ¹Fakultät für Physik and CENIDE, Universität Duisburg-Essen, Germany — ²Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany — ³Institut für Theoretische Physik, Technische Universität Dresden, Germany

We study relaxation dynamics in a strongly-interacting three and four-site Fermi-Hubbard system (quantum dots) coupled to environment represented by fermionic baths. We analyze the simply frustrated (trimer) and doubly frustrated (tetrahedron) spin geometries to observe the relaxation to steady states containing persistent or oscillating spin currents. Due to high sensitivity of these results to the coherence of the final state, we can test several variants of the Lindblad master equations, derived under different assumptions and parameter regimes: local and global, secular and coherent.
[1] E. Kleinherbers, N. Szpak, J. König, and R. Schützhold, Phys. Rev. B 101, 125131 (2020)
[2] G. Schaller, F. Queisser, N. Szpak, J. König, and R. Schützhold, Phys. Rev. B 105, 115139 (2022)
[3] N. Szpak, G. Schaller, R. Schützhold and J. König, Phys. Rev. B 110, 115131 (2024)

Keywords: quantum dots; Lindblad master equation; relaxation; Fermi-Hubbard model