Engineering atomic superradiance scaling in cavity QED system with collective and individual emission channels

TL;DR

The paper addresses how to control superradiant scaling in multi-atom cavity QED by coupling atoms to a single leaky cavity mode. It employs semiclassical phase-space techniques — the truncated Wigner approximation for collective emission and discrete truncated Wigner approximation for independent emission — to access large $N$ dynamics under dissipation. The main findings show that the cavity can suppress the ideal $N^2$ scaling of collective emission to about $N^{1.76}$ at moderate coupling, while enabling near-quadratic scaling $N^{1.89}$ for ensembles emitting independently via the shared reservoir. This work provides a practical route to engineer and tune many-atom radiance in state-of-the-art platforms, with potential applications in quantum information processing and precision metrology.

Abstract

The coherent emission of multiple atoms gives rise to superradiance, a cornerstone phenomenon in quantum optics with wide-ranging applications in quantum information processing and precision metrology. Despite its importance, how the superradiant scaling with respect to the number of participating atoms can be effectively controlled remains largely unexplored. In this work, we investigate a cavity-QED system and demonstrate that atom-photon coupling can significantly alter the emission behavior--suppressing the collective superradiant scaling while enhancing the scaling associated with individual atomic emissions. Our study provides a pathway toward controllable collective emission in state-of-the-art experimental platforms.

Figures (4)

• Figure 1: Schematic illustration of the collective emission process in a multi-atom cavity QED system. The cavity mode decays at a rate $2\kappa$, and the atomic ensemble exhibits collective radiation with an effective decay rate $2\Gamma$.
• Figure 2: (a) Atomic dynamical evolution $2\langle S_z\rangle/N$ with collective emission, obtained from the TWA and mean-field approximation for atom numbers $N=100$ and $N=500$ with the atom-cavity coupling strength being $g = 10\Gamma$. (b) Log-log plot of the superradiance strength $I$ versus atom number $N$ for different coupling strengths $g$, while solid lines represent the fitted curves obtained from a power-law fit. The parameters are chosen as $\omega_a = \omega$ and $\kappa = \Gamma$.
• Figure 3: Schematic illustration of the individual emission process in a multi-atom cavity QED system. The cavity mode decays at a rate $2\kappa$, and the atoms exhibit individual emission with a decay rate $2\gamma$.
• Figure 4: (a) Atomic dynamical evolution $2\langle S_z\rangle/N$ with collective emission, obtained from the TWA and mean-field approximation for atom numbers $N=100$ and $N=500$ with the atom-cavity coupling strength being $g = 2\gamma$. (b) Log-log plot of the superradiance strength $I$ versus atom number $N$ for different coupling strengths $g$, while solid lines represent the fitted curves obtained from a power-law fit. The parameters are chosen as $\omega_a = \omega$ and $\kappa = 20\gamma$.