91̽��

Unravelling the origin of unconventional superconductivity is one of the central motivations for quantum simulations with ultracold fermionic atoms in optical lattices. In addition, next-generation lattice systems are bringing the construction of a fermionic quantum computer within reach, promising applications to a much wider range of quantum problems.

In these experiments, we cool lithium-6 atoms to a few nanokelvin, load them into periodic potentials formed by light, and probe the strongly correlated quantum many-body states using single-atom-resolved images of hundreds of atoms. 

In the first part of the talk, I will present studies of the hole-doped two-dimensional Hubbard model using the Munich lithium quantum gas microscope. Focusing on the competition between short-ranged antiferromagnetic order and dopant motion, believed to underlie superconductivity and related phases, we directly observe magnetic polarons, demonstrate magnetically mediated hole pairing and stripe formation, and present a large-scale study of magnetic scaling at the onset of the pseudogap phase [1,2,3].

In the second part, I will introduce double wells created by optical superlattices as elementary building blocks for quantum-computing hardware [4,5]. In these two-site systems, we achieve full control over the quantum state through gates acting on both the spin and spatial degrees of freedom. Controlled collisions realise a two-particle gate with 99.75%–fidelity [5], opening the door to locally programmable gate arrays and digital–analogue hybrid simulations. Finally, I will outline progress towards a fermionic quantum computer in my lab and its near-term applications.

[1] Hirthe, S. et al., Nature 613 463 (2023).

[2] Bourgund, D. et al., Nature 637 57 (2025).

[3] Chalopin, T. et al., PNAS. 123, e2525539123 (2026).

[4] Chalopin, T. et al., Phys. Rev. Lett. 134 053402 (2025).

[5] Bojović, P. et al., Nature, in press (2026), arXiv:2506.14711.