Dresden 2026 – scientific programme

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MA: Fachverband Magnetismus

MA 34: Computational Magnetism I

MA 34.10: Talk

Wednesday, March 11, 2026, 17:30–17:45, HSZ/0004

operator Lanczos approach enabling neural quantum states as real frequency impurity solvers — •Jonas Rigo¹ and Markus Schmitt^1,2 — ¹Forschungszentrum Jülich GmbH, Peter Grünberg Institute, Quantum Control, 52425 Jülich, Germany — ²University of Regensburg

To understand the intricate exchange between electrons of different bands in strongly correlated materials, it is essential to treat multi-orbital models accurately. For this purpose, dynamical mean-field theory (DMFT) provides an established framework, whose scope crucially hinges on the availability of efficient quantum impurity solvers. Here we present a real-frequency impurity solver based on neural quantum states (NQS) combined with an operator-space Lanczos construction. NQS are an asymptotically unbiased variational ground-state ansatz that employs neural networks to capture long-range correlations on complicated graph structures. We leverage this ability to solve complex multi-orbital impurity problems using a systematically improvable segmented commutator operator Lanczos (SCOL) construction. Our benchmarks on both the single-orbital Anderson model and the multi-orbital Hubbard–Kanamori impurity Hamiltonian reveal excellent ground state precision and the capacity to resolve key features of zero temperature spectral functions and self-energies. These promising results open avenues for extending DMFT to more challenging problems.

Keywords: DMFT; neural quantum states; NQS; multi-orbital; Hunds metal