Mainz 2026 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 24: Ultra-cold Atoms, Ions and BEC I (joint session A/Q)

Q 24.5: Talk

Tuesday, March 3, 2026, 12:00–12:15, N 1

Topological Order in Symmetric Blockade Structures — •Tobias Florian Maier, Hans Peter Büchler, and Nicolai Lang — Institute for Theoretical Physics III and Center for Integrated Quantum Science and Technology, University of Stuttgart, 70550 Stuttgart, Germany

The bottom-up design of strongly interacting quantum materials with prescribed ground-state properties is a highly nontrivial task, especially if only simple constituents with realistic two-body interactions are available on the microscopic level. We study two- and three-dimensional structures of two-level systems that interact via a simple blockade potential in the presence of a coherent coupling between the two states. For such strongly interacting quantum many-body systems, we introduce the concept of blockade graph automorphisms to construct symmetric blockade structures with strong quantum fluctuations that lead to equal-weight superpositions of tailored states. Drawing from these results, we design a quasi two-dimensional periodic quantum system that – as we show rigorously – features a topological Z₂ spin liquid as its ground state. Our construction is based on the implementation of a local symmetry on the microscopic level in a system with only two-body interactions [1].

[1] T. F. Maier, H. P. Büchler and N.Lang, Topological Order in Symmetric Blockade Structures, PRX Quantum 6(3) (2025), doi:10.1103/dtlf-2q82.

Keywords: Topological order; Toric code; Quantum spin liquid; Quantum simulation; Strongly interacting quantum systems