AI 中文总结
本研究采用非微扰量子动力学框架，揭示三维玻色气体冷却猝灭后，平衡态凝聚阈值兼具动力学临界点功能，发现直接猝灭至阈值时存在新临界不动点，确立了凝聚相变的非平衡对应物。
AI 中文摘要
采用非微扰量子动力学框架，我们对三维玻色气体在跨越玻色-爱因斯坦凝聚相变的冷却猝灭后的远离平衡态动力学建立了统一描述。通过追踪动量分布的时空演化，我们发现平衡态凝聚阈值同时作为动力学临界点，分隔由不同非平衡吸引子支配的不同远离平衡态普适类。在相变以上的猝灭表现为朝向热不动点的单时间尺度弛豫，在相变以下的猝灭则呈现从瞬态弱湍流 regime 到由涡旋线扩散复合支配的粗化不动点的 crossover。直接猝灭至凝聚阈值的情况最终由一种此前未被发现的临界不动点支配，该不动点的特征是临界涨落的超扩散传播以及一组独特的动力学指数。这些动力学标度律共同确立了凝聚相变的远离平衡态对应物，其中平衡态临界点也组织着长时间的非平衡动力学。
英文摘要
Using a non-perturbative quantum kinetic framework, we develop a unified description of the far-from-equilibrium dynamics of three-dimensional Bose gases following cooling quenches across the Bose-Einstein condensation transition. By tracking the spatio-temporal evolution of the momentum distribution, we show that the equilibrium condensation threshold simultaneously acts as a dynamical critical point, separating distinct far-from-equilibrium universality classes governed by different non-equilibrium attractors. While quenches above the transition exhibit a single-timescale relaxation toward a thermal fixed point, quenches below the transition display a crossover from a transient weak-turbulence regime to a coarsening fixed point governed by the diffusive recombination of vortex lines. Quenches directly to the condensation threshold, finally, are controlled by a previously unidentified critical fixed point characterized by the superdiffusive spreading of critical fluctuations and a distinct set of dynamical exponents. Together, these dynamical scaling laws establish a far-from-equilibrium counterpart of the condensation phase transition, in which the equilibrium critical point also organizes the long-time non-equilibrium dynamics.
