Department of Physics, Georgetown University, Washington, DC 20057, USA.
Phys Rev Lett. 2012 Dec 28;109(26):260402. doi: 10.1103/PhysRevLett.109.260402.
We use a self-consistent strong-coupling expansion for the self-energy (perturbation theory in the hopping) to describe the nonequilibrium dynamics of strongly correlated lattice fermions. We study the three-dimensional homogeneous Fermi-Hubbard model driven by an external electric field showing that the damping of the ensuing Bloch oscillations depends on the direction of the field and that for a broad range of field strengths a long-lived transient prethermalized state emerges. This long-lived transient regime implies that thermal equilibrium may be out of reach of the time scales accessible in present cold atom experiments but shows that an interesting new quasiuniversal transient state exists in nonequilibrium governed by a thermalized kinetic energy but not a thermalized potential energy. In addition, when the field strength is equal in magnitude to the interaction between atoms, the system undergoes a rapid thermalization, characterized by a different quasiuniversal behavior of the current and spectral function for different values of the hopping.
我们使用自洽强耦合展开（跃迁中的微扰理论）来描述强关联晶格费米子的非平衡动力学。我们研究了在外部电场驱动下的三维均匀费米-哈伯德模型，结果表明，随之而来的布洛赫振荡的阻尼取决于场的方向，并且在广泛的场强范围内，会出现一个长寿命的瞬态预热态。这种长寿命的瞬态意味着，在目前的冷原子实验可达到的时间尺度内，可能无法达到热平衡，但表明在由热化动能而非热化势能控制的非平衡中存在一个有趣的新准通用瞬态。此外，当场强与原子间相互作用相当时，系统会经历快速热化，其特点是电流和光谱函数的不同准通用行为，具体取决于跃迁的不同值。
