Erlangen 2018 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 19: Cold atoms IV - topological systems (joint session A/Q)
Q 19.1: Talk
Monday, March 5, 2018, 16:15–16:30, K 0.011
Properties of the one-particle density matrix in an interacting Chern insulator — •Andrew Hayward1, Marie Piraud2, and Fabian Heidrich-Meisner2,3 — 1LMU, Munich, Germany — 2TU, Munich, Germany — 3Georg-August-University Goettingen, Germany
The notion of a topological insulator is rooted in the physics of non-interacting particles but generalizes to interacting systems. Here we investigate how much the topological properties of an interacting Chern insulator are encoded in the single-particle quantities derived from the one-particle density matrix (OPDM) computed in the many-body ground state. The diagonalization of the OPDM yields the occupation spectrum and its eigenfunctions. In a concrete example we study how the occupations evolve as a function of interactions and how the eigenfunctions are deformed away from the non-interacting limit. After resolving potential ambiguities in defining OPDM eigenbands,we compute the Chern numbers for these emergent OPDM bands,which are necessarily quantized. The behavior of these quantities, occupations, OPDM eigenfunctions, and OPDM Chern numbers, across a transition into a topologically trivial phase is discussed.This research is supported by DFG Research Unit FOR2414.