Super-Radiant Dynamics, Doorways, and Resonances in Nuclei and Other Open Mesoscopic Systems

TL;DR

This paper reviews super-radiance phenomena in open quantum systems, highlighting how strong continuum coupling leads to resonance restructuring, with applications across nuclear, atomic, and particle physics, and explores related doorway states and mesoscopic conductance.

Contribution

It provides a comprehensive formalism based on non-Hermitian Hamiltonians for understanding super-radiance and doorway states in open mesoscopic systems, with detailed applications and connections to chaos and conductance.

Findings

Resonance restructuring into super-radiant and trapped states at strong continuum coupling

Formalism based on Feshbach projection and non-Hermitian Hamiltonian

Applications demonstrated in nuclear, atomic, and particle physics

Abstract

The phenomenon of super-radiance (Dicke effect, coherent spontaneous radiation by a gas of atoms coupled through the common radiation field) is well known in quantum optics. The review discusses similar physics that emerges in open and marginally stable quantum many-body systems. In the presence of open decay channels, the intrinsic states are coupled through the continuum. At sufficiently strong continuum coupling, the spectrum of resonances undergoes the restructuring with segregation of very broad super-radiant states and trapping of remaining long-lived compound states. The appropriate formalism describing this phenomenon is based on the Feshbach projection method and effective non-Hermitian Hamiltonian. A broader generalization is related to the idea of doorway states connecting quantum states of different structure. The method is explained in detail and the examples of applications are given to nuclear, atomic and particle physics. The interrelation of the collective dynamics through continuum and possible intrinsic many-body chaos is studied, including universal mesoscopic conductance fluctuations. The theory serves as a natural framework for general description of a quantum signal transmission through an open mesoscopic system.