Breaking the Exponential: Decoherence-Driven Power-Law Spontaneous Emission in Waveguide Quantum Electrodynamics

TL;DR

This paper demonstrates that dynamical dephasing in waveguide QED systems transforms the typical exponential decay of a two-level emitter into a robust power-law decay at short times, revealing a new decoherence-driven emission mechanism.

Contribution

It introduces a novel mechanism where decoherence induces power-law decay in spontaneous emission, contrasting with traditional spectral edge effects.

Findings

Dephasing causes early-time power-law decay in emission.

Photon diffusion in disordered environments drives the decay.

Power-law decay is robust and observable at short times.

Abstract

We investigate the spontaneous emission of a two-level system coupled to a photonic waveguide, showing that dynamical dephasing in the photon modes profoundly alters the decay law. In the absence of dephasing, the emitter displays conventional exponential decay followed by a long-time power-law tail -- observable only at extremely low survival probabilities. Strikingly, when dephasing is introduced, a robust power-law decay emerges already at short times, driven by photon diffusion in the dynamically disordered environment rather than spectral edge effects. These results reveal a novel, decoherence-induced mechanism for non-exponential spontaneous emission in waveguide QED platforms.