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arXiv · 2202.05033

Floquet engineering topological Dirac bands

Mingwu Lu·G. H. Reid·A. R. Fritsch·A. M. Piñeiro·I. B. Spielman
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Abstract

We experimentally realized a time-periodically modulated 1D lattice for ultracold atoms featuring a pair of linear bands, each associated with a Floquet winding number: a topological invariant. These bands are spin-momentum locked and almost perfectly linear everywhere in the Brillouin zone (BZ), making this system a near-ideal realization of the 1D Dirac Hamiltonian. We characterized the Floquet winding number using a form of quantum state tomography, covering the BZ and following the micromotion through one Floquet period. Lastly, we altered the modulation timing to lift the topological protection, opening a gap at the Dirac point that grew in proportion to the deviation from the topological configuration.

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Mingwu Lu, G. H. Reid, A. R. Fritsch, A. M. Piñeiro, I. B. Spielman. 2022-02-10. Floquet engineering topological Dirac bands. https://doi.org/10.1103/physrevlett.129.040402

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