Interaction-driven topological excitations in optical lattices with bosons

11 October 2016

Photo: AG Hemmerich

Most many-body quantum states in nature may be categorized in terms of broken symmetries. Often it is the translational symmetry that is broken, for example, if water crystallizes to form ice. However, nature provides an additional ordering principle for quantum matter, namely topology. Topological materials, although insulating in the bulk, may carry quantized charge or spin currents at the edges, which can persist even in the presence of impurities. The use of bosonic atoms loaded into an optical lattice opens up an entirely new world of possible topological quantum systems not realized in electronic condensed matter.In two new works published in Physical Review Letters we propose and study two optical lattice scenarios that do not yield topological properties for a single atom, while in the case of many interacting atoms intriguing new states of matter emerge, which exhibit topological excitations on top of non-topological chiral ground states showing interaction-driven vortical currents.

M. Di Liberto, A. Hemmerich, and C. Morais Smith
Physical Review Letters 117, 163001 (2016)

Z.-F. Xu, Li You, A. Hemmerich, W. V. Liu
Physical Review Letters 117, 085301 (2016)