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arXiv · 2601.14217

Many-body Euler topology

Axel Fünfhaus·Titus Neupert·Thilo Kopp·Roser Valentí
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Abstract

Integer and fractional Chern insulators exhibit a nonzero quantized anomalous Hall conductivity due to a spontaneous breaking of time reversal symmetry. To identify nontrivial topology in their time-reversal symmetric many-body spectra, we introduce many-body Euler numbers as a counterpart to many-body Chern numbers. Exemplarily, we perform calculations in a topological Hubbard model that can realize Chern and fractional Chern insulating phases. Furthermore, we lay out a classification scheme to realize different topological phases in interacting systems using symmetry indicators in analogy to topological band theory.

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Axel Fünfhaus, Titus Neupert, Thilo Kopp, Roser Valentí. 2026-01-20. Many-body Euler topology. https://arxiv.org/abs/2601.14217

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