Hannover 2013 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 56: Poster III
Q 56.35: Poster
Donnerstag, 21. März 2013, 16:00–18:30, Empore Lichthof
Negative absolute temperature and out-of-equilibrium dynamics of interacting bosons in optical lattices — •Michael Schreiber1,2, Simon Braun1,2, Jens Philipp Ronzheimer1,2, Daniel Garbe1,2, Sean Hodgman1,2, Immanuel Bloch1,2, and Ulrich Schneider1,2 — 1LMU München — 2MPQ Garching
Absolute temperature is usually bound to be strictly positive. However, in systems with an upper energy bound, negative absolute temperature states are possible, in which the occupation probability of states increases with their energy. We realised a negative absolute temperature state for motional degrees of freedom using ultracold bosonic 39K atoms in an optical lattice.
This new state strikingly revealed itself by strong occupation peaks at maximum kinetic energy. We found that the negative absolute temperature state is as stable as the corresponding positive temperature state. We also studied how coherence emerges in a slow quench from an incoherent attractive Mott insulator at negative temperature and compared it to the positive temperature case.
Additionally, we investigated the out-of-equilibrium expansion dynamics of interacting bosons in one- and two-dimensional Hubbard systems. We found that the fastest, ballistic expansions occur in the integrable limits. For non-integrable systems the expansion slows down significantly as diffusive dynamics set in.