Stuttgart 2012 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 21: Quantengase: Optische Gitter 1
Q 21.7: Talk
Tuesday, March 13, 2012, 12:00–12:15, V53.01
Sauter-Schwinger like tunneling in tilted Bose-Hubbard lattices — Friedemann Queisser2, •Patrick Navez1, and Ralf Schützhold2 — 1Institut für Theoretische Physik, Technische Universität Dresden, 01062 Dresden, Germany — 2Fakultät für Physik, Universität Duisburg-Essen, Lotharstrasse 1, 47057 Duisburg, Germany
We study the Mott phase of the Bose-Hubbard model on a tilted lattice.
In the limit of large coordination numbers Z (i.e,. tunneling partners),
we establish a hierarchy of correlations via a 1/Z-expansion.
On the (Gutzwiller) mean-field level, the tilt has no effect – but
quantum fluctuations entail particle-hole pair creation via tunneling.
For small potential gradients (long-wavelength limit), we derive a
quantitative analogy to the Sauter-Schwinger effect, i.e.,
electron-positron pair creation out of the vacuum by an electric field.
For large tilts, we obtain resonant tunneling
reminiscent of Bloch oscillations.
References: arXiv:1107.3730v1, Phys. Rev. A 82, 063603 (2010)