par Asteria, Luca;Tran, Duc-Thanh ;Ozawa, Tomoki ;Tarnowski, Matthias;Rem, Benno S.;Fläschner, Nick;Sengstock, Klaus;Goldman, Nathan ;Weitenberg, Christof
Référence Nature physics
Publication Publié, 2019-02-01
Référence Nature physics
Publication Publié, 2019-02-01
Lettre à l'éditeur
Résumé : | The topology of two-dimensional materials traditionally manifests itself through the quantization of the Hall conductance, which is revealed in transport measurements 1–3 . Recently, it was predicted that topology can also give rise to a characteristic spectroscopic response on subjecting a Chern insulator to a circular drive: comparing the frequency-integrated depletion rates associated with drives of opposite orientation leads to a quantized response dictated by the topological Chern number of the populated Bloch band 4,5 . Here we experimentally demonstrate this intriguing topological effect using ultracold fermionic atoms in topological Floquet bands. In addition, our depletion-rate measurements also provide an experimental estimation of the Wannier-spread functional, a fundamental geometric property of Bloch bands related to the quantum metric 6,7 . Our results establish topological spectroscopic responses as a versatile probe, which could be applied to access the geometry and topology of many-body quantum systems, such as fractional Chern insulators 8 . |