Photon-mediated dipole-dipole interactions as a resource for quantum science and technology in cold atoms

Photon-mediated dipole-dipole interactions arise from atom-light interactions, which are universal and prevalent in a wide range of open quantum systems. This pairwise and long-range spin-exchange interaction results from multiple light scattering among the atoms. A recent surge of interests and progresses in both experiments and theories promises this core mechanism of collective interactions as a resource to study quantum science and to envision next-generation applications in quantum technology. Here we present recent developments in theories, where we focus on cooperative light scattering from small sample of free-space atoms, an atom-waveguide coupled interface that hosts the waveguide QED, and topological quantum optical platforms. Our results showcase the essential and distinct features of collective dynamics induced by resonant dipole-dipole interactions and to reveal unprecedented opportunities in enhancing the performance or offering new applications in quantum state engineering and measurement-based quantum computations.