Schedule Mar 15, 2013
Confinement Modifies Interactions of Ultracold Dipolar Gases on Optical Lattices
Michael Wall (Colorado School of Mines)

Michael L. Wall and Lincoln D. Carr

Department of Physics, Colorado School of Mines

We study the effective dipole-dipole interactions in an ultracold quantum gas loaded into an optical lattice.  As opposed to the 1/r^3 decay of interactions between dipoles separated by a distance r in free space, we find that the effective interaction in the lattice decays exponentially with separation at short distance and has a long-range power law tail.  The increased effective interaction is due to large quantum fluctuations from the heavy-tailed localized single-particle probability distributions, and also relies crucially on imbalance in confinement due to the d-wave anisotropy of the dipole-dipole interaction.  The effect can be sizable in quasi-low dimensional confined scenarios; we identify differences of up to 36% from the free-space interaction at the nearest-neighbor distance in quasi-1D arrangements.  Using matrix product state simulations on infinite quasi-one-dimensional lattices, we demonstrate that use of the correct lattice dipolar interaction leads to significant deviations from many-body predictions using the free-space interaction in the lattice.

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