论文标题
孤立的量子系统中的概率滞后：从量子角度出发不可逆性的微观发作
Probabilistic Hysteresis in an Isolated Quantum System: The Microscopic Onset of Irreversibility from a Quantum Perspective
论文作者
论文摘要
最近，已经研究了较大的粒子数量的极限，在半经典治疗足够的情况下，已经研究了孤立的哈密顿原子系统中的概率滞后。在这些扫描实验中，不可逆性的起源是，控制参数缓慢地（绝热）来回调音，结果是在分离质（可集成的情况）中来回蓝色，或在相位空间中进出混乱的海洋（Chaotic Case）中的一段和段落。在这里，我们关注可集成系统的完整量子机械描述，并显示半经典结果如何以大粒子数的极限出现。量子系统中不可逆的不可逆性的起源是一系列避免的绝热能量水平的穿越：它们变得如此接近，以至于对于适度的粒子数量，外部参数的变化已经不现实地降低，以达到量子的变化，以达到量子的变化，以达到量子的变化，以达到量子的降低，以达到量子的降低，以达到量子的变化，以达到量子的变化，以达到量子的变化，以达到量子的降低，以达到量子，以达到量子，以达到量子，以达到量子的速度，以达到量子的降低，以达到量子的降低，以达到量子，而不是在相位空间中穿过分离型的分离。对于缓慢而有限的扫描率，我们发现量子结果与半经典结果一致的广泛制度，但只有除了极限$ n \ to \ infty $外，还考虑了最初的状态集合，并具有足够的初始能量宽度。对于单个初始能量本征态，我们发现向后扫描即使对于非常大的粒子数也显示出强大的量子效应。
Recently probabilistic hysteresis in isolated Hamiltonian systems of ultracold atoms has been studied in the limit of large particle numbers, where a semiclassical treatment is adequate. The origin of irreversibility in these sweep experiments, where a control parameter is slowly (adiabatically) tuned back and forth, turned out to be a passage blue back and forth across a separatrix (integrable case) or a passage in and out of a chaotic sea in phase space (chaotic case). Here we focus on the full quantum mechanical description of the integrable system and show how the semiclassical results emerge in the limit of large particle numbers. Instead of the crossing of a separatrix in phase space, where classical adiabaticity fails, the origin of irreversibility in the quantum system is a series of avoided crossings of the adiabatic energy levels: they become so close that already for modest particle numbers the change of the external parameter has to be unrealistically slow to reach the quantum adiabatic limit of perfectly reversible evolution. For a slow but finite sweep rate we find a broad regime where the quantum results agree with the semiclassical results, but only if besides the limit $N\to \infty$ an initial ensemble of states is considered, with sufficient initial energy width. For a single initial energy eigenstate we find in contrast that the backward sweep reveals strong quantum effects even for very large particle numbers.
