Unconventional Density Wave and Superfluidity in Cold Atom Systems
CALIFORNIA UNIV RIVERSIDE
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Ultra-cold atom system provides novel technology to simulate traditional solid state physics, including boson and fermion particles. Due to the flexibility of tuning parameters, people can further understand basic physics behind strongly correlated effects, especially mechanism of unconventional density wave and superfluidity. Using weak coupling renormalization group method, we propose and study several models which can be realized in experiments. Ranging from most well-known extended Hubbard model, to spin-polarized Fermi Hubbard model and multi-flavor Fermi-Fermi mixture, we establish solid theories to explain the origin of new states of matter, and the experimental techniques to exploit them. The effects of lattice structure and particle density in fermionic system play important roles for determining phase diagram in low energy scale. Due to the presence of lattice, these systems have insulator phase at half-filling. The density imbalance, however, prevents formation of conventional density wave state, and the screening interaction dramatically affects other speciess behavior. The interplay between screening interaction and square lattice is key ingredient of unconventional density wave and superfluidity. Our study shows that the unconventional density wave and superfluidity can be realized and detected in ultra-cold atom experiments.
- Fluid Mechanics
- Atomic and Molecular Physics and Spectroscopy