Density-dependent synthetic gauge fields for cold atoms in optical lattices
Prof. Dr. Luis Santos (Institut für Theoretische Physik, Universität Hannover)

The realization of synthetic magnetism constitutes a major breakthrough in the physics of ultra-cold gases. However, the fields created are static since there is no back action of the atoms on the fields. I will discuss on how density-dependent fields may be created and how they influence the properties of lattice gases.

After a brief discussion on the realization of 1D models with density-dependent fields using periodically-modulated interactions [1,2], I will focus on the use of Raman-assisted hopping to create density-dependent magnetism and a two-body hard-core constraint (2BHCC). In 1D this scheme results in an anyon-Hubbard model. The combination of anyon statistics and 2BHCC leads to Mott phases at attractive interactions, dimer phases, and more relevantly to a novel two-component superfluid [3]. Density-dependent fields lead also to a non-trivial interplay between density modulations and chirality in ladders and square lattices, including density-driven Meissner- to vortex-superfluid transition, and a peculiar doublon/holon dynamics in a Mott insulator [4].

[1] S. Greschner et al., PRL 113, 215303 (2014).
[2] S. Greschner et al., PRL 113, 183002 (2014).
[3] S. Greschner et al., PRL (in press, 2015),arXiv:1501.07462.
[4] S. Greschner et al., arXiv:1502.07944.