We discuss the preparation of topological insulator states with fermionic ultracold atoms in optical lattices by means of measurement-based Markovian feedback control. The designed measurement and feedback operators induce an effective dissipative channel that stabilizes the desired insulator state, either in an exact way or approximately in the case where additional experimental constraints are assumed. Successful state preparation is demonstrated in one-dimensional insulators as well as for Haldane's Chern insulator, by calculating the fidelity between the target ground state and the steady state of the feedback-modified master equation. The fidelity is obtained numerically through exact diagonalization or via time evolution of the system with moderate sizes. For larger 2D systems, we compare the mean occupation of the single-particle eigenstates for the ground and steady state computed through mean-field kinetic equations.
Thermodynamics of the three-dimensional Hubbard model: Implications for cooling cold atomic gases in optical lattices
本文对三维费米子哈伯德模型的热力学性质进行了全面的研究，并将其应用于受光晶格和囚禁势约束的冷费米子原子。我们的研究集中在当前实验感兴趣的温度范围内。我们采用两种理论方法-动态平均场论和高温系列-和执行比较基准，以界定各自的有效性范围。特别注意的是，致力于了解这个系统的热力学性质对冷却的影响。考虑到非均匀晶格中的局域占位分布函数，我们证明了，在绝热演化下，任何可观测的变化（例如，温度）可以方便地分解成两个不同的贡献。第一个贡献是由于演化过程中陷阱中原子的重新分布，而第二个贡献来自于可观测的内在变化。最后，我们提供了J. - S. Bernier等人，Phys. Rev. A 79，061601（2009）通过将该方法应用于理想化模型来计算。
