Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 69: Other Low Temperature Topics: Cold Atomic Gases

TT 69.1: Talk

Wednesday, March 18, 2015, 15:00–15:15, A 053

Strongly Correlated Phases and Ferromagnetic Phases of Fermions in an Optical Flux Lattice Model — •Simon Davenport and Nigel Cooper — Cavendish Laboratory, 19 J J Thomson Avenue, Cambridge, CB3 0HE

We study a theoretical model of a 2-dimensional ultracold atomic gas subject to an ``optical flux lattice'': a particular laser configuration where Raman-dressed atoms experience a strong effective magnetic field, which can lead to a bandstructure of narrow energy bands with non-zero Chern numbers. In this optical flux lattice we place spin-1/2 fermions that interact via a Feshbach-resonance induced contact interaction, coupling spin-up and spin-down particles. Atoms restricted to the lowest band are described by an effective model of spinless fermions with a tunable interaction coupling states in a momentum-dependent manner across the Brillouin zone. This non-local interaction is due to the Raman coupling between spin-up and spin-down levels. We present a summary of results from a detailed exact diagonalization study of the effective lowest band model. In particular we offer evidence indicating the presence of strongly correlated phases and ferromagnetic phases.