Bound state in a giant atom-modulated resonators system

It is of fundamental interest in controlling the light–matter interaction for a long time in the field of quantum information processing. Here, we explore a model by coupling a giant atom with the dynamically-modulated coupled-resonator waveguide and find the bound state, where the light shows the localization effect and the atomic decay into resonator modes is inhibited, excited by a propagating photon. An analytical treatment based on the separation of the propagating states and localized states of light has been proposed and provides inspiring explanation of our finding, i.e., there supports a quantum channel where the propagating photon can be converted to the localized state through the quantum interference from light–atom interactions in three resonators at different frequency detunings. Our work therefore shows the potential for actively localizing the photon in a modulated coupled-resonator waveguide system interacting with the giant atom, and also points out a way to study the light–atom interaction in a synthetic frequency dimension that holds the similar Hamiltonian.