Yoshimura Takato, Sá Lucas
All Souls College, Oxford, UK.
Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford, UK.
Nat Commun. 2024 Nov 12;15(1):9808. doi: 10.1038/s41467-024-54164-7.
Dissipation is a ubiquitous phenomenon that affects the fate of chaotic quantum many-body dynamics. Here, we show that chaos can be robust against dissipation but can also assist and anomalously enhance relaxation. We compute exactly the dissipative form factor of a generic Floquet quantum circuit with arbitrary on-site dissipation modeled by quantum channels and find that, for long enough times, the system always relaxes with two distinctive regimes characterized by the presence or absence of gap-closing. While the system can sustain a robust ramp for a long (but finite) time interval in the gap-closing regime, relaxation is "assisted" by quantum chaos in the regime where the gap remains nonzero. In the latter regime, we prove that, if the thermodynamic limit is taken first, the gap does not close even in the dissipationless limit. We complement our analytical findings with numerical results for quantum qubit circuits.
耗散是一种普遍存在的现象，它影响着混沌量子多体动力学的演化。在此，我们表明混沌对耗散可以具有鲁棒性，但也可以辅助并异常增强弛豫。我们精确计算了由量子信道建模的具有任意局域耗散的一般弗洛凯量子电路的耗散形状因子，发现对于足够长的时间，系统总是以两种不同的状态弛豫，其特征是能隙是否关闭。虽然在能隙关闭状态下系统可以在很长（但有限）的时间间隔内维持一个鲁棒的斜坡，但在能隙保持非零的状态下，弛豫由量子混沌“辅助”。在后一种状态下，我们证明，如果首先取热力学极限，即使在无耗散极限下能隙也不会关闭。我们用量子比特电路的数值结果补充了我们的分析发现。
