Dresden 2026 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 33: Correlated Magnetism – Dynamics and Spectroscopy

TT 33.6: Talk

Tuesday, March 10, 2026, 12:15–12:30, HSZ/0105

Control of chiral topological phases: Dynamics of a chiral spin liquid — •Ruben Burkard and Urban Friedrich Peter Seifert — Institut für Theoretische Physik, Universität Köln, Zülpicher Straße 77a, 50937 Köln, Germany

As recent advances in experiment make it increasingly feasible to realize and control unconventional quantum many-body states, we investigate the out-of-equilibrium dynamics of a chiral spin liquid, with the aim of drawing lessons for the control of topologically ordered phases. In particular, we consider the Hubbard model on the triangular lattice near the Mott transition, which can be described by an effective spin model with higher-order interaction terms and is believed to host a CSL phase. In order to drive the system out of equilibrium, we apply ultrafast optical pulses, which couple to the spins in the system via magnetoelectric couplings and induce nonthermal, reversible modifications to the system’s effective spin Hamiltonian. These can be derived from an appropriate Hubbard model in a Floquet approach. We then formulate a time-dependent parton mean-field theory to study the light-induced dynamics of the magnetic degrees of freedom. From this study, one might also infer lessons for other systems with chiral topological order, such as fractional quantum anomalous Hall (FQAH) states recently observed (and optically controlled) in twisted MoTe₂, or chiral pseudospin liquids in Moiré heterostructures.

Keywords: Topological Phases; Chiral Phases; Floquet Theory; Quantum Spin Liquids; Parton Mean-Field Theory