Dresden 2011 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 31: Quantum Gases: Opt. Lattice 2
Q 31.3: Talk
Wednesday, March 16, 2011, 15:00–15:15, HSZ 02
Néel transition of lattice fermions in a harmonic trap: a real-space dynamical mean-field study — •Elena V. Gorelik1, Irakli Titvinidze2, Walter Hofstetter2, Michiel Snoek3, and Nils Blümer1 — 1Institute of Physics, Johannes Gutenberg University, Mainz, Germany — 2Institute for Theoretical Physics, Johann Wolfgang Goethe University, Frankfurt, Germany — 3Institute for Theoretical Physics, University of Amsterdam, The Netherlands
Ultracold atoms on optical lattices attract enormous interest as potential “quantum simulators” of condensed-matter systems. A missing link in this context is the realization of antiferromagnetic (AF) Néel phases: in spite of enormous experimental efforts, concentrating in particular on achieving lower temperatures, no AF signatures have been detected so far.
We extend the range of applicability of the recently developed real-space dynamical mean-field theory (DMFT) to the temperatures of experimental interest by combining it with a highly efficient quantum Monte Carlo algorithm [1]. We demonstrate that the onset of AF correlations at low temperatures is signaled, for interactions U > 10t, by a strongly enhanced double occupancy [2]. This signature is directly accessible experimentally and should be observable well above the critical temperature for long-range order. Dimensional aspects appear less relevant (and DMFT more accurate) than naively expected.
[1] N. Blümer and E. V. Gorelik, Comp. Phys. Comm. 182, 115 (2011). [2] E. V. Gorelik, I. Titvinidze, W. Hofstetter, M. Snoek, and N. Blümer, Phys. Rev. Lett. 105, 065301 (2010).