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Interacting fermion ladders are important platforms to study quantum phases of matter including various Mott insulators with different symmetry properties, such as the D-Mott and S-Mott phase. The latter hold pre-formed electron pairs and become paired liquids (d-wave and s-wave) upon doping. These Mott insulators were believed to be distinct phases (see e.g. the classical textbook “Quantum physics in one dimension”). We demonstrate that this understanding is incomplete: They are in fact two facets of the same interaction-induced topological phase. With this, we provide a quantum analog of the well-known terminable liquid-gas transition. However, the phenomenology we uncover is even richer, as in contrast to the liquid-gas transition, the order of the transition can be tuned by the interaction and bears relevance for the topological properties of the system. These results show interesting synergy between fundamental questions in the fields of fermion pairing, topology, Mott insulators and terminated phase transitions.

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Roman Rausch, TU Braunschweig
Seminar Room 0.03, ETP (+Zoom, if requested)
Contact: Matteo Rizzi