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arXiv · 1711.09538

Reduction of topological $\mathbb{Z}$ classification in cold atomic systems

Tsuneya Yoshida·Ippei Danshita·Robert Peters·Norio Kawakami
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Abstract

One of the most challenging problems in correlated topological systems is a realization of the reduction of topological classification, but very few experimental platforms have been proposed so far. We here demonstrate that ultracold dipolar fermions (e.g., $^{167}$Er, $^{161}$Dy, and $^{53}$Cr) loaded in an optical lattice of two-leg ladder geometry can be the first promising testbed for the reduction $\mathbb{Z}\to\mathbb{Z}_4$, where solid evidence for the reduction is available thanks to their high controllability. We further give a detailed account of how to experimentally access this phenomenon; around the edges, the destruction of one-particle gapless excitations can be observed by the local radio frequency spectroscopy, while that of gapless spin excitations can be observed by a time-dependent spin expectation value of a superposed state of the ground state and the first excited state. We clarify that even when the reduction occurs, a gapless edge mode is recovered around a dislocation, which can be another piece of evidence for the reduction.

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Tsuneya Yoshida, Ippei Danshita, Robert Peters, Norio Kawakami. 2017-11-27. Reduction of topological $\mathbb{Z}$ classification in cold atomic systems. https://doi.org/10.1103/physrevlett.121.025301

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