On the eigenstates of Spin-Exchange model for fermionic atoms with large spin in optical lattice

The simplest model describing behavior of atoms in optical lattice is the Hubbard model — it contains on-site repulsion of atoms and tunneling between nearest neighboring sites. In the limit of repulsive interaction being way larger than tunneling, the system goes in to the regime restricted to states with exactly one atom in each site. The dynamics of the system is then described by effective model called Spin-Exchange model (SE), containing effective nearest neighbor interaction and spin exchange.

For atomic spin s=1/2 the SE model exhibits behavior identical like Heisenberg model (nearest neighbors dipolar interaction). For any larger spins s ≥ 1 SE model still share some properties of Heisenberg, but on the other hand many of its features are dramatically different!

Although some authors are aware that for large spins SE is not Heisenberg, it seems that hardly anyone sees the physical consequence of this difference. This difference is however very fundamental – it is enough to say that the eigenstates of these two models are different.

In my talk I will present the SE model, derive its eigenstates and show the physical consequences of such a set of eigenstates for dynamics of the system.

Zoom:

https://us06web.zoom.us/j/87057373249?pwd=MNnyk4rUf9cOVZoxeqIaKkhwYk5STm.1

Location:

seminar room D, CFT PAN Al. Lotników / Zoom