California Institute of Technology, Pasadena, California 91125, USA.
Phys Rev Lett. 2011 Sep 9;107(11):115301. doi: 10.1103/PhysRevLett.107.115301. Epub 2011 Sep 8.
By selecting two dressed rotational states of ultracold polar molecules in an optical lattice, we obtain a highly tunable generalization of the t-J model, which we refer to as the t-J-V-W model. In addition to XXZ spin exchange, the model features density-density interactions and density-spin interactions; all interactions are dipolar. We show that full control of all interaction parameters in both magnitude and sign can be achieved independently of each other and of the tunneling. As a first step towards demonstrating the potential of the system, we apply the density matrix renormalization group method to obtain the 1D phase diagram of the simplest experimentally realizable case. Specifically, we show that the tunability and the long-range nature of the interactions in the t-J-V-W model enable enhanced superfluidity. Finally, we show that Bloch oscillations in a tilted lattice can be used to probe the phase diagram experimentally.
通过选择超冷极性分子在光晶格中的两种 dressed 旋转态，我们得到了一个高度可调谐的 t-J 模型推广，我们称之为 t-J-V-W 模型。除了 XXZ 自旋交换，该模型还具有密度-密度相互作用和密度-自旋相互作用；所有相互作用都是偶极子的。我们表明，可以独立于隧道相互作用以及独立于隧道相互作用，对所有相互作用参数的幅度和符号进行完全控制。作为展示该系统潜力的第一步，我们应用密度矩阵重整化群方法来获得最简单的实验可实现情况的 1D 相图。具体来说，我们表明，在 t-J-V-W 模型中，相互作用的可调谐性和长程性质可以增强超流性。最后，我们表明，倾斜晶格中的布洛赫振荡可以用于实验探测相图。
