$N$ Scaling of Large-Sample Collective Decay in Inhomogeneous Ensembles

TL;DR

This study investigates how collective decay rates scale with the number of atoms in a disordered ensemble within a hollow-core fiber, revealing limits to N-scaling due to inhomogeneities and proposing an effective emitter model for optimization.

Contribution

The paper introduces an effective number of emitters to recover N-scaling in inhomogeneous ensembles, providing new insights into collective decay limits and optimization strategies.

Findings

Observed up to 300-fold decay rate enhancement

Data deviates from N-scaling due to inhomogeneities

Effective emitter model restores N-scaling over large parameters

Abstract

We experimentally study collective decay of an extended disordered ensemble of $N$ atoms inside a hollow-core fiber. We observe up to $300$-fold enhanced decay rates, strong optical bursts and a coherent ringing. Due to inhomogeneities limiting the synchronization of atoms, the data does not show the typical scaling with $N$. We show that an effective number of collective emitters can be determined to recover the $N$ scaling known to homogeneous ensembles over a large parameter range. This provides physical insight into the limits of collective decay and allows for its optimization in extended ensembles as used, e.g., in quantum optics, precision time-keeping or waveguide QED.