Chaotic scattering of a quantum particle weakly coupled to a very complicated background

TL;DR

This paper investigates how a complex many-body environment influences the chaotic behavior of a quantum particle in a mesoscopic structure, highlighting effects on dephasing, absorption, and delay time fluctuations.

Contribution

It introduces a model that unifies dephasing and absorption effects without ambiguities, emphasizing the role of background states and spreading width in quantum chaos.

Findings

Background states cause additional damping of resonance states.

Formation of fine-structure resonances increases delay time fluctuations.

Internal damping is characterized by the spreading width.

Abstract

Effect of a complicated many-body environment is analyzed on the chaotic motion of a quantum particle in a mesoscopic ballistic structure. The dephasing and absorption phenomena are treated on the same footing in the framework of a model which is free of the ambiguities inherent to earlier models. The single-particle doorway resonance states excited via an external channel are damped not only because of the escape onto such channels but also due to ulterior population of long-lived background states, the resulting internal damping being uniquely characterized by the spreading width. On the other hand, the formation of the fine-structure resonances strongly enhances the delay time fluctuations thus broadening the delay time distribution.