# Online: Seminar, Gian Michele Graf (ETH Zurich), Topology in Shallow-Water Waves: A Violation of Bulk-Edge Correspondence #### calendar\_today Date and Time **December 15, 2020** 10:00AM - 10:00AM EST #### pin\_drop Location **Zoom** ![Gian Michele Graf](/sites/g/files/omnuum6611/files/styles/hwp_1_1__720x720_scale/public/mathpicture/files/graf.png?itok=mVkqYlzy) **Location:** Zoom **Time:** Tuesday, December 15, 2020, 10:00 AM (Eastern US), 15:00 (UK/Eire), 16:00 (Central Europe), 23:00 (China) **Title:** Topology in Shallow-Water Waves: A Violation of Bulk-Edge Correspondence **Abstract:** A two-dimensional rotating shallow-water model describes a layer of water, in guise of oceans covering the Earth. It is formally analogue to a Schrödinger equation where the tools from topological insulators are relevant. Once regularized at small scale by an odd-viscous term, such a model has a well-defined bulk topological index. However, in presence of a sharp boundary, the number of edge modes depends on the boundary condition, showing an explicit violation of the bulk-edge correspondence. We study a continuous family of boundary conditions with a rich phase diagram, and explain the origin of this mismatch. Our approach relies on scattering theory and Levinson’s theorem. The latter does not apply at infinite momentum because of the analytic structure of the scattering amplitude there, which is ultimately the reason for the violation. (Joint work with H. Jud and C. Tauber.) **Additional Ways to Join** Join by telephone (use any number to dial in) +1 929 436 2866 +1 312 626 6799 +1 669 900 6833 400 669 9381 China Toll-free International numbers available: [https://harvar](https://harvard.zoom.us/u/aclg6kOggb)[d.zoom.us/u/aclg6kOggb](https://harvard.zoom.us/u/aclg6kOggb) One tap mobile: +19294362866,,779283357# US (New York) Join by SIP conference room system Meeting ID: 779 283 357 <779283357@zoomcrc.com> **Attachments** --- Attachments- [ picture\_as\_pdf Flyer.pdf ](/sites/g/files/omnuum6611/files/mathpicture/files/graf_december_15_2020_seminar_flyer.pdf) --- Share on:- [ Facebook ](#) - [ Twitter ](#) - [ Linkedin ](#) Save: [ Add to calendar calendar\_today ](https://mathpicture.fas.harvard.edu/node/1544819/event-feed.ics) Copy link link