Regensburg 2025 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 17: Correlated Electrons: Method Development
TT 17.5: Vortrag
Dienstag, 18. März 2025, 10:30–10:45, H33
Simulating two-dimensional fermionic systems with strong correlations using Neural Quantum States — •Hannah Lange1,2,3, Annika Böhler1,2, Christopher Roth4, and Annabelle Bohrdt5,2 — 1LMU Munich — 2Munich Center for QST, Munich — 3Max-Planck-Institute for Quantum Optics, Garching — 4Flatiron Institute, New York — 5University of Regensburg
Simulating strongly interacting fermionic systems is crucial for understanding correlated phases like unconventional superconductivity, yet it remains a challenge for numerical and experimental methods in many cases. Here, I will discuss the efficiency and accuracy of fermionic neural quantum states (NQS), in particular hidden fermion determinant states (HFDS), for simulating doped quantum magnets. I will show results on the strongly interacting limit of the Fermi-Hubbard model across the entire doping regime. The HFDS achieve energies competitive with matrix product states (MPS) on lattices as large as 8 x 8 sites while using several orders of magnitude fewer parameters. This efficiency enables us to probe low-energy physics across the full doping range: Starting from the low-doping regime, where magnetic polarons dominate, we track their evolution with doping through spin and polaron correlations and compare them with experimental measurements. Furthermore, I will discuss different initializations of NQS, including a hybrid training scheme, which improves the training by incorporating experimental measurements. Our findings open the way for simulating large-scale fermionic systems at any particle filling.
Keywords: Neural quantum states; t - J model; Fermi Hubbard model; Magnetic Polarons