An exciting frontier in quantum information science is the creation and manipulation of quantum systems that are built and controlled quanta-by-quanta. In this context, there is active research worldwide to achieve lithographic quantum optical circuits, for which atoms are trapped in nanoscopic dielectric structures and wired by photons propagating through complex circuit elements. I will discuss a designer’s method to create synthetic quantum matter utilizing neutral atoms embedded in photonic crystal waveguides. The strong interplays between quantum excitations of spins, light, and sound are all utilized to create the effective “gauge" bosons that mediate arbitrary Hamiltonians in the spin matter. I will also discuss a new regime of analog quantum spin-ice models and more generally string-net models that are accessible by strongly-coupled cavity Rydberg polaritons. In the pursuits of both research directions, I will complement the theoretical descriptions with the experimental progresses in the Laboratory of Ultracold Quantum Matter & Light (UQML) at the University of Waterloo.