论文标题
高温病毒扩展到通用淬灭动力学
High Temperature Virial Expansion to Universal Quench Dynamics
论文作者
论文摘要
高温病毒膨胀是平衡统计力学的强大工具。在这封信中，我们概括了高温病毒膨胀方法，以治疗远程平衡的淬灭动力学。作为我们框架的应用，我们研究了从非相互作用到统一性淬灭的bose气体的动力学，并将理论结果与剑桥组的无法解释的实验结果进行比较[Eigen等人[Eigen等，Nature 563，221（2018）]。我们表明，在淬灭动力学期间，低摩托姆部分的动量分布以$ k <k^*$的形式降低，并以$ k> k^*$的高度零件增加，其中$ k^*$是一个特征性的动量，将低 - 和高莫曼特姆制度分开。我们确定与实验完全一致的$ k^*λ$的通用价值，其中$λ$是thermal de broglie波长。我们还发现$ k^*λ$的中途放松时间和能量分布的非单调性行为的跳跃，这两者都与实验一致。最后，我们解决了长期稳态是否热效应的问题，我们发现该状态确实会热力化，除了具有$Kλ\ gg 1 $的高动量尾巴。我们的框架也可以应用于其他系统中的动态。
High temperature virial expansion is a powerful tool in equilibrium statistical mechanics. In this letter we generalize the high temperature virial expansion approach to treat far-from-equilibrium quench dynamics. As an application of our framework, we study the dynamics of a Bose gas quenched from non-interacting to unitarity, and we compare our theoretical results with unexplained experimental results by the Cambridge group [Eigen et al., Nature 563, 221 (2018)]. We show that, during the quench dynamics, the momentum distribution decreases for low-momentum part with $k<k^*$, and increases for high-momentum part with $k>k^*$, where $k^*$ is a characteristic momentum scale separating the low- and the high-momentum regimes. We determine the universal value of $k^*λ$ that agrees perfectly with the experiment, with $λ$ being the thermal de Broglie wave length. We also find a jump of the half-way relaxation time across $k^*λ$ and the non-monotonic behavior of energy distribution, both of which agree with the experiment. Finally, we address the issue whether the long-time steady state thermalizes or not, and we find that this state does thermalize except for the very high momentum tail with $kλ\gg 1$. Our framework can also be applied to quench dynamics in other systems.
