Correlated photon emission by two excited giant atoms coupled to a one-dimensional waveguide
Phys. Rev. A 113, 043726 – Published 21 April, 2026
DOI: https://doi.org/10.1103/xm9r-8qcn
Abstract
We theoretically investigate spontaneous photon-pair emission from a pair of excited giant atoms coupled to a waveguide. We analyze three distinct coupling configurations: separate, braided, and nested. The system decays via two independent channels, and the resulting two-photon wave function is governed by their quantum interference, which is controllable by tuning the self- and cross-interference phases. We show that these phases provide enhanced control over the directionality of the two-photon emission in the braided configuration. Furthermore, they facilitate a transition from photon bunching to antibunching for counterpropagating photons. Notably, the braided and nested configurations exhibit oscillatory behavior with an increased correlation length. The nested configuration is unique in that it can generate antibunched photons even when they are copropagating. Our results illustrate that giant atoms offer advantageous control over photon-pair properties—including emission directionality, quantum statistics, and correlation length—compared to conventional small atoms.
