From superradiance to collective EIT in three-level ensembles

TL;DR

This paper explores the connection between superradiance and EIT in three-level atomic ensembles, revealing how collective effects influence emission intensity, response, and slow-light capabilities, with implications for quantum technologies.

Contribution

It introduces a unified theoretical framework linking superradiant emission and EIT in three-level systems, including a master equation that accurately models both regimes.

Findings

Superradiant burst scales as N^2 with finite-size corrections

Collective broadening enhances group velocity despite increased absorption

Cooperative interactions limit slow-light delay in dense media

Abstract

We investigate the collective dynamics of a three-level ensemble under the Dicke limit, revealing a unified connection between superradiant emission and electromagnetically induced transparency (EIT). Our results show that the transient superradiant burst exhibits the expected peak intensity scaling $I_{\max}\!\sim\! N^2$, with a universal finite-size correction $|\xi(N)-2|\!\sim\! 1/\ln N$ that governs the apparent scaling exponent in realistic ensembles. In the stationary regime, collective broadening modifies the EIT response: although it typically enhances absorption, it counterintuitively increases the group velocity, leading to a relative scaling $v_g\!\propto\! N^2$, even while $v_g\!\ll\! c$. This effect suggests that cooperative interactions fundamentally limit the achievable slow-light delay in dense media. To achieve these results, we derive a representative-atom master equation that quantitatively reproduces both the superradiant and EIT regimes, in excellent agreement with the exact symmetric-subspace dynamics and correctly incorporating collective feedback and $N$-dependent broadening. This unified framework bridges transient superradiant emission and steady-state quantum interference, with direct implications for slow light, quantum memories, and precision metrology.