Atoms trapped by laser light have become excellent platforms for simulating condensed matter physics and beyond. These systems are also playgrounds for exploring quantum many-body phenomena and even uncovering new phenomena not yet seen in nature. In this talk I will start with a brief introduction and then show close ties between cold atomic physics and other many-body systems. Further, I will review a mean-field-like theory we developed for the normal phase of unitary fermions and the calculation of spin diffusion currents of one-dimensional lattice fermions based on thermodynamic Bethe ansatz approach and local-density approximation. The final part of the talk is devoted to discuss our ongoing and immediate-future theoretical efforts on understanding many-body physics associates with cold atoms.
