Regensburg 2022 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 13: Quantum Dots, Quantum Wires, Point Contacts

TT 13.6: Talk

Tuesday, September 6, 2022, 10:45–11:00, H23

Relaxation dynamics in a Hubbard trimer and tetramer coupled to fermionic baths: antiferromagnetic order and persistent spin currents — •Nikodem Szpak¹, Gernot Schaller², Friedemann Queisser², Ralf Schützhold^2,3, and Jürgen König¹ — ¹Theoretische Physik, Universität Duisburg-Essen, Lotharstr. 1, 47048 Duisburg — ²Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328 Dresden — ³Institut für Theoretische Physik, Technische Universität Dresden, 01062 Dresden

We study relaxation dynamics in a strongly-interacting three and four-site Fermi-Hubbard system (quantum dots) coupled to environment represented by fermionic baths. Starting with an ab initio approach, we derive several variants of the Lindblad master equation for the quantum dots systems by applying different approaches: local and global, secular and coherent [1,2]. At low temperatures, depending on the particular parameter ratios and applied approximations, the system tends to or destroys antiferromagnetic order [2]. In three quantun dots, the system becomes spin-frustrated and relaxes to a stable persistent spin current.

[1] E. Kleinherbers, N. Szpak, J. König, and R. Schützhold, Phys. Rev. B 101, 125131

[2] G. Schaller, F. Queisser, N. Szpak, J. König, and R. Schützhold, Phys. Rev. B 105, 115139