Dynamics of weakly interacting bosons in optical lattices with flux

Hudomal, Ana and Vasić, Ivana and Buljan, Hrvoje and Hofstetter, Walter and Balaž, Antun (2018) Dynamics of weakly interacting bosons in optical lattices with flux. Physical Review A, 98 (5). pp. 53625-16. ISSN 1050-2947

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Abstract

Realization of strong synthetic magnetic fields in driven optical lattices has enabled implementation of topological bands in cold-atom setups. A milestone has been reached by a recent measurement of a finite Chern number based on the dynamics of incoherent bosonic atoms. The measurements of the quantum Hall effect in semiconductors are related to the Chern-number measurement in a cold-atom setup; however, the design and complexity of the two types of measurements are quite different. Motivated by these recent developments, we investigate the dynamics of weakly interacting incoherent bosons in a two-dimensional driven optical lattice exposed to an external force, which provides a direct probe of the Chern number. We consider a realistic driving protocol in the regime of high driving frequency and focus on the role of weak repulsive interactions. We find that interactions lead to the redistribution of atoms over topological bands both through the conversion of interaction energy into kinetic energy during the expansion of the atomic cloud and due to an additional heating. Remarkably, we observe that the moderate atomic repulsion facilitates the measurement by flattening the distribution of atoms in the quasimomentum space. Our results also show that weak interactions can suppress the contribution of some higher-order nontopological terms in favor of the topological part of the effective model.

Item Type: Article
Date: November 2018
Subjects: NATURAL SCIENCES > Physics
Additional Information: © 2018 American Physical Society. Received 19 September 2018; Published 26 November 2018.
Divisions: Faculty of Science > Department of Physics
Publisher: American Physical Society
Depositing User: Gordana Stubičan Ladešić
Date Deposited: 27 Mar 2019 16:39
Last Modified: 27 Mar 2019 16:40
URI: http://digre.pmf.unizg.hr/id/eprint/5900

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