Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 69: Other Low Temperature Topics: Cold Atomic Gases

TT 69.8: Vortrag

Mittwoch, 18. März 2015, 16:45–17:00, A 053

Tight binding models for ultracold atoms using maximally localized Wannier functions — •Julen Ibañez-Azpiroz¹, Asier Eiguren^2,3, Aitor Bergara^2,3, Giulio Pettini⁴, and Michele Modugno^2,5 — ¹Peter Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, D-52425 Jülich, Germany — ²Universidad del Pais Vasco, Bilbao, Spain — ³Donostia International Physics Center, Spain — ⁴Universita di Firenze and INFN, Italy — ⁵Ikerbasque, Basque Foundation for Science, Spain

We discuss how to construct tight-binding models for weakly interacting ultracold atoms using maximally localized Wannier functions (MLWFs) [1]. The resulting models are shown to accurately describe the properties of the continuous systems with the use of few tunneling coefficients. First we work out a simple honeycomb lattice model directly related to the graphene physics [2]. Next we generalize the approach for including a vector potential and analyze a possible implementation of the Haldane model. We show that the commonly employed Peierls substitution does not yield a reasonable description of the effect of the vector potential on the tunneling coefficients [3], which in turn affects the topological phase diagram.

JIA acknowledges support from Helmholtz Gemeinschaft Deutscher-Young Investigators Group Program No. VH-NG- 717 (Functional Nanoscale Structure and Probe Simulation Laboratory).

[1] N. Marzari and D. Vanderbilt Phys. Rev. B 56, 12847 (1997)

[2] J. Ibañez-Azpiroz et al., Phys. Rev. A 87, 011602(R) (2013)

[3] J. Ibañez-Azpiroz et al., Phys. Rev. A 90, 033609 (2014)