Multimode-cavity picture of non-Markovian waveguide QED

• DOI: 10.48550/arxiv.2403.07110
• Publication Date: 2024-03-11
• Authors: Dario Cilluffo; Luca Ferialdi; G. Massimo Palma; Giuseppe Calajò; Francesco Ciccarello
• Keywords: Waveguide

We introduce a picture to describe and intrepret waveguide-QED problems in the non-Markovian regime of long photonic retardation times resulting delayed coherent feedback. The framework is based on an intuitive spatial decomposition waveguide into blocks. Among these, block directly coupled atoms embodies effective lossy multimode cavity leaking rest waveguide, turn embodying white-noise bath. dynamics can be approximated by retaining only finite number modes that yet eventually grows with time delay. This description captures atomic as well field's dynamics, even many excitations, both emission scattering processes. As application, we show recently identified steady states understood very few or one modes.