Bound states and entanglement generation in waveguide quantum electrodynamics

TL;DR

This paper explores how two quantum emitters in a waveguide can form stable entangled bound states, which are significant for quantum information, especially near resonance conditions where decay is suppressed.

Contribution

It introduces a detailed analysis of bound states in waveguide QED, highlighting their formation, stability, and role in entanglement generation near resonance conditions.

Findings

Bound states occur at specific resonant interatomic distances.

Entangled bound states can form even when single atoms decay.

Non-resonant bound states have energies below photon propagation threshold.

Abstract

We investigate the behavior of two quantum emitters (two-level atoms) embedded in a linear waveguide, in a quasi-one-dimensional configuration. Since the atoms can emit, absorb and reflect radiation, the pair can spontaneously relax towards an entangled bound state, under conditions in which a single atom would instead decay. We analyze the properties of these bound states, which occur for resonant values of the interatomic distance, and discuss their relevance with respect to entanglement generation. The stability of such states close to the resonance is studied, as well as the properties of non resonant bound states, whose energy is below the threshold for photon propagation.