Hunt for symmetry-protected topological phases in SU(N) ultra-cold fermions in one-dimensional optical lattices

  • Event Date: 2018-11-14
  • AMO/QIS/CMT
  • Speaker: Prof. Keisuke Totsuka (Yukawa Institute, Kyoto University)  /  Host: Prof. Sungkit Yip (Institute of Physics, Academia Sinica)
    Place: Lecture Room A of NCTS, 4F, 3rd General Building, Nat'l Tsing Hua Univ.

Discovery of topological insulators and superconductors sparked extensive study on topological phases of matter that are protected by the presence of certain symmetries. Although fairly complete catalogs of these symmetry-protected topological (SPT) phases have been obtained with various mathematical methods [1,2], physical systems that realize the proposed topological phases are little known. In this talk, I will discuss how an interesting family of SPT phases can be realized in a realistic setting using ultra-cold fermion atoms (e.g., alkaline-earth or Yb) which are known to possess exact SU(N) "spin" symmetry. In particular, we show that, in a one-dimensional array of double wells, SPT phases with spontaneously broken inversion symmetry (chiral SPT phases) emerges as a consequence of interplay between "SU(N)-spin" and orbital degrees of freedom.


References
[1] A. Schnyder et al., Phys.Rev.B, 78, 195125 (2008); A Kitaev, AIP Conference Proceedings, 2009, 1134, 22
[2] X. Chen, Z.C. Gu, and X-G. Wen, Phys.Rev.B, 87, 155114(2013); N.Schuch et al, Phys.Rev.B, 84, 165139 (2011).
[3] H. Nonne, M. Moliner, S. Capponi, P. Lecheminant, and K. Totsuka,EPL, 102,37008 (2013); V. Bois, S. Capponi, P. Lecheminant, M.Moliner, and K. Totsuka, Phys.Rev.B, 91, 075121 (2015)
[3] P. Fromholz, S. Capponi, P. Lecheminant, and K. Totsuka, arXiv:1709.10409; S. Capponi, P. Fromholz, P. Lecheminant, and K. Totsuka, in preparation.

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