Date(s) - 20/11/2013
3:30 pm - 4:30 pm
Title: Can Bosons Condense in Excited States?
Speaker: Dr. Andreas Hemmerich
Institute: UniversitÃ¤t Hamburg, Institut fÃ¼r Laser-Physik
Location: ABB 102
Bosons at very low temperatures are known to be subject to the phenomenon of Bose-Einstein condensation, leading to a macroscopic population of the ground state. The many-body wave function thus formed is positive real under most general circumstances and hence topologically trivial as has been early pointed out by Feynman. However, under certain conditions, condensation can also occur in metastable excited states, which can lead to highly non-trivial superfluid order. I will introduce the experimental laboratory of optical lattices, a model arena where atomic gases crystallized in a web of light are used to simulate ultracold condensed matter, and discuss our recent observations of unconventional forms of superfluidity in metastable higher bands.