Volume 102, Number 3, May 2013
|Number of page(s)||6|
|Section||Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties|
|Published online||20 May 2013|
Symmetry-protected topological phases of alkaline-earth cold fermionic atoms in one dimension
1 Department of Physics, Technion - Haifa 32000, Israel
2 Laboratoire de Physique Théorique et Modélisation, CNRS UMR 8089, Université de Cergy- Pontoise Site de Saint-Martin, F-95300 Cergy- Pontoise Cedex, France, EU
3 Laboratoire de Physique Théorique, CNRS UMR 5152, Université Paul Sabatier - F-31062 Toulouse, France, EU
4 Yukawa Institute for Theoretical Physics, Kyoto University - Kitashirakawa Oiwake-Cho, Kyoto 606-8502, Japan
Received: 27 January 2013
Accepted: 23 April 2013
We investigate the existence of symmetry-protected topological phases in one-dimensional alkaline-earth cold fermionic atoms with general half-integer nuclear spin I at halffilling. In this respect, some orbital degrees of freedom are required. They can be introduced by considering either the metastable excited state of alkaline-earth atoms or the p-band of the optical lattice. Using complementary techniques, we show that SU(2) Haldane topological phases are stabilised from these orbital degrees of freedom. On top of these phases, we find the emergence of topological phases with enlarged SU(2I + 1) symmetry which depend only on the nuclear-spin degrees of freedom. The main physical properties of the latter phases are further studied using a matrix-product state approach. On the one hand, we find that these phases are symmetry-protected topological phases, with respect to inversion symmetry, when which is directly relevant to ytterbium and strontium cold fermions. On the other hand, for the other values of I(=half-odd integer), these topological phases are stabilised only in the presence of exact SU(2I + 1) symmetry.
PACS: 71.10.Pm – Fermions in reduced dimensions (anyons, composite fermions, Luttinger liquid, etc.) / 75.10.Pq – Spin chain models
© EPLA, 2013
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