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ResercherID: Y. Hatsugai
投稿者 : hatsugai 投稿日時： 2016-01-16 17:16:48 (69 ヒット)
Topological pump, proposal by Thouless and just recently realized experimeatally in Kyoto and Munich independently, is revisited from the bulk-edge correspondence (BEC). It's typically described by well known Harper equation as in QHE but the view point of BEC supplies quite different physical / mathematical structure. Pumped charge is carried by bulk but its quantization is guaranteed by the topological number defined by a singular motion of the center of mass caused by edge states. However this singular motion can not be observed in reality by a pumping of finite speed.The edge states are hidden! Counting the topological number by singularities of the spectral flow is a standard technique in the discussion of the Atiyah-Patodii-Singer index theorem. The same counting appears in the BEC in the pumping. It's a unexpected surprise. Have a look at arXiv:1601.03537
投稿者 : hatsugai 投稿日時： 2016-01-16 17:16:20 (397 ヒット)
Our paper is now online. Topology is not only for quantum world. Localised modes near the system boundaries also exist in a classical system that is predicted by bulk. This is the bulk-edge correspondence originally discussed in quantum systems such as quantum (spin) Hall states and graphene. Still this idea is valid in classical world. We discussed topological phenomena in mechanics for point particles connected with springs in a honeycomb shape. Also topological phase transitions associated with its tension is clearly demonstrated as a time evolution of the localized modes. [arXiv:1505.06679]
Coming event : Program is ready: International workshop "physics of bulk-edge correspondence & its universality"
投稿者 : hatsugai 投稿日時： 2015-09-14 19:50:18 (701 ヒット)
We are organizing an international workshop on the bulk-edge correspondence / topological phases Sep. 27-29 (2015) in Tokyo (Myogadani) supported by KAKENHI (JSPS research funding). Tentative program is ready and on the net.