November 15 at 13:30 - 15:00, 2021 (JST)
Prof. Naoto Nagaosa (Deputy Director, Group Director, Strong Correlation Theory Research Group, RIKEN Center for Emergent Matter Science (CEMS) / Professor, Department of Applied Physics, School of Engineering, The University of Tokyo)
via Zoom

Studies on optical responses of solids have the long history, and has been considered to be well established. However, a new development has been on-going recently, which explores the geometric nature of the electronic states in solids and its crucial role in optical processes.
In this talk, I discuss the geometry and topology in the optical responses both in linear and nonlinear regimes, which includes (i) optical responses in clean superconductors, (ii) shift current in noncentrosymmetric quantum materials driven by Berry phases, and (iii) Riemannian geometry in nonlinear optical responses.

*If you would like to participate, please contact Hidetoshi Taya.


  1. J. Ahn and N. Nagaosa, Theory of optical responses in clean multi-band superconductors, Nature Communications 12, 1617 (2021), doi: 10.1038/s41467-021-21905-x
  2. T. Morimoto and N. Nagaosa, Topological nature of nonlinear optical effects in solids, Science Advances, Vol 2, Issue 5 (2016), doi: 10.1126/sciadv.1501524
  3. J. Ahn, G.Y, Guo and N.Nagaosa, Low-Frequency Divergence and Quantum Geometry of the Bulk Photovoltaic Effect in Topological Semimetals, Physical Review X, Volume 10, Issue 4 (2020), doi: 10.1103/PhysRevX.10.041041
  4. J. Ahn, G.Y, Guo, N.Nagaosa, A. Vishwanath, Nature Phys. To appear

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