发表机构
Institute of Theoretical Physics, Shanxi University; State Key Laboratory of Quantum Optics Technologies and Devices, Shanxi University; Collaborative Innovation Center of Extreme Optics, Shanxi University（山西大学理论物理研究所; 山西大学量子光学与光量子器件国家重点实验室; 山西大学极端光学协同创新中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文利用精确Bethe ansatz方法研究一维吸引相互作用费米气体中自旋翻转杂质的淬火动力学，揭示弱吸引与强吸引区域的束缚态及振荡行为，并表征量子颤动现象，为超冷原子杂质实验提供理论支持。
AI 中文摘要
量子多体系统中的杂质非平衡动力学是超冷原子物理中的一个前沿课题，有助于揭示极化子和集体激发现象的微观机制。尽管排斥相互作用系统已被广泛研究，但由于不同状态之间复杂的耦合，吸引相互作用动力学缺乏系统性研究。我们研究了一个包含具有初始动量的吸引自旋向下杂质的一维理想费米气体，并分析了自旋间两体关联和杂质动量的时间演化。利用精确的Bethe ansatz解，我们将关联矩阵元简化为有限和，以高效计算本征态占据数和长时间动力学演化。在弱吸引区域，当总动量低于或等于费米动量时出现束缚态特征，而在更大的总动量下则出现混合振荡行为。强吸引区域表现出局域束缚态主导的动力学，具有局域化关联峰和散射诱导的类弗里德尔振荡。我们表征了量子颤动，即杂质动量的周期性振荡，并通过四种独立的Bethe ansatz方法获得了一致的杂质临界化学势值。这项工作阐明了吸引相互作用下的淬火动力学和量子颤动，增进了对非平衡量子多体性质的理解，并为相关的超冷原子杂质实验提供了理论支持。
英文摘要
Impurity nonequilibrium dynamics in quantum many-body systems is a frontier subject in ultracold-atom physics, which helps uncover microscopic mechanisms of polaron and collective excitation phenomena. Although repulsive interacting systems have been extensively investigated, attractive-interaction dynamics lacks systematic studies owing to intricate couplings among different states. We study a one-dimensional ideal Fermi gas containing an attractive spin-down impurity with initial momentum and analyze time evolution of interspin two-body correlations and impurity momentum. Using exact Bethe ansatz solutions, we simplify correlation matrix elements to finite sums for efficient calculations of eigenstate occupations and long-time dynamical evolution. In the weakly attractive regime, bound-state features appear when the total momentum is below or equal to the Fermi momentum, while mixed oscillatory behaviors arise at larger total momentum. The strongly attractive regime shows locally bound-state dominated dynamics with localized correlation peaks and scattering-induced Friedel-like oscillations. We characterize quantum flutter, the periodic oscillation of impurity momentum, and obtain consistent critical chemical potential values of the impurity via four independent Bethe ansatz approaches. This work clarifies quench dynamics and quantum flutter under attractive interactions, improves the understanding of nonequilibrium quantum many-body properties, and provides theoretical support for relevant ultracold-atom impurity experiments.
Comments30 pages, 7 figures
Journal refActa Phys. Sin., 2026, 75(11): 110305
