Collective radiance of giant atoms in non-Markovian regime

We investigate the non-Markovian dynamics of two giant artificial atoms interacting with a continuum of bosonic modes in a one-dimensional (1D) waveguide. Based on the diagrammatic method, we present the exact analytical solutions, which predict the rich phenomena of collective radiance. For the certain collective states, the decay rates are found to be far beyond that predicted in the the Dicke model and standard Markovian framework, which indicates the occurrence of super-superradiance. The superadiance-to-subradiance transition could be realized by adjusting the exchange symmetry of giant atoms. Moreover, there exist multiple bound states in continuum (BICs), with photons/phonons bouncing back and forth in the cavity-like geometries formed by the coupling points. The trapped photons/phonons in the BICs can also be re-released conveniently by changing the energy level splitting of giant atoms. The mechanism relies on the joint effects of the coherent time-delayed feedback and the interference between the coupling points of giant atoms. This work fundamentally broadens the fields of giant atom collective radiance by introducing non-Markovianity. It also paves the way for a clean analytical description of the nonlinear open quantum system with more complex retardation.

Automated summary

We investigate the non-Markovian dynamics of two giant artificial atoms interacting with a continuum of bosonic modes. Exact analytical solutions are presented, predicting the phenomena of collective radiance. The occurrence of super-superradiance and the transition from superadiance to subradiance are found, and multiple bound states in continuum (BICs) are observed. The trapped photons/phonons in BICs can be easily released by changing the energy level splitting of giant atoms.