Large-amplitude superexchange of high-spin fermions in optical lattices
Abstract
We show that fermionic high-spin systems with spin-changing collisions allow one to monitor superexchange processes in optical superlattices with large amplitudes and strong spin fluctuations. By investigating the non-equilibrium dynamics, we find a superexchange dominated regime at weak interactions. The underlying mechanism is driven by an emerging tunneling-energy gap in shallow few-well potentials. As a consequence, the interaction-energy gap that is expected to occur only for strong interactions in deep lattices is re-established. By tuning the optical lattice depth, a crossover between two regimes with negligible particle number fluctuations is found: firstly, the common regime with vanishing spin-fluctuations in deep lattices and, secondly, a novel regime with strong spin fluctuations in shallow lattices. We discuss the possible experimental realization with ultracold 40K atoms and observable quantities in double wells and two-dimensional plaquettes.
- Publication:
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New Journal of Physics
- Pub Date:
- November 2013
- DOI:
- 10.1088/1367-2630/15/11/113017
- arXiv:
- arXiv:1306.1330
- Bibcode:
- 2013NJPh...15k3017J
- Keywords:
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- Condensed Matter - Quantum Gases;
- Quantum Physics
- E-Print:
- 13 pages, 6 figures