Interaction-induced topology in ultracold atoms

Objetivo

Topological phases aTopological phases are among the most intriguing topics in solid-state physics, because they fall outside the classification via local order parameters and their topologically protected excitations promise important applications. For a deeper understanding of these phases, quantum simulation with ultracold atoms in optical lattices can make an important contribution, because they allow for a clean and tunable realization of paradigmatic model systems and provide advanced detection schemes such as snapshots of the particle distribution. Previous work relied on Floquet engineering for inducing topology and the accompanying heating processes fundamentally limited these studied. InToCold will instead study interaction-induced topological phases without Floquet engineering and realize important phases such as chiral and topological bosonic superfluids and Mott insulators and their topological excitations. This will be enabled by introducing a new way of realizing different bipartite and tripartite optical lattices in a tunable and phase-stable manner and by preparing the atoms in the p-bands of these lattices, where on-site interactions lead to loop currents with spontaneous symmetry breaking. Furthermore, as a central technique, an advanced microscopy built on matter-wave imaging with ultrahigh resolution well below the lattice spacing will allow to directly image the hybridized orbitals for the first time and therefore study these phases with microscopic detail. A phase microscopy will allow to directly image the staggered loop currents as well as phase domains. Finally, InToCold will introduce a new scheme to implement dominant nearest neighbour imaging built on an optically-controlled Feshbach resonance, which allows to prepare and study chiral Mott insulators and their excitations. This project will therefore contribute to the microscopic understanding of topological phases and open entirely new route of quantum simulation with ultracold atoms.