Exciting a Bound State in the Continuum through Multi-Photon Scattering plus Delayed Quantum Feedback
Abstract
Excitation of a bound state in the continuum (BIC) through scattering is problematic since it is by definition uncoupled. Here, we consider a type of dressed BIC and show that it can be excited in a nonlinear system through multi-photon scattering and delayed quantum feedback. The system is a semi-infinite waveguide with linear dispersion coupled to a qubit, in which a single-photon, dressed BIC is known to exist. We show that this BIC can be populated via multi-photon scattering in the non-Markovian regime, where the photon delay time (due to the qubit-mirror distance) is comparable with the qubit's decay. A similar process excites the BIC existing in an infinite waveguide coupled to two distant qubits, thus yielding stationary entanglement between the qubits. This shows, in particular, that single-photon trapping via multi-photon scattering can occur without band-edge effects or cavities, the essential resource being instead the {\it delayed} quantum feedback provided by a single mirror or the emitters themselves.
Cite
@article{arxiv.1811.02582,
title = {Exciting a Bound State in the Continuum through Multi-Photon Scattering plus Delayed Quantum Feedback},
author = {Giuseppe Calajò and Yao-Lung L. Fang and Harold U. Baranger and Francesco Ciccarello},
journal= {arXiv preprint arXiv:1811.02582},
year = {2019}
}
Comments
5 pages, 5 figures, supplementary material