Inhomogeneous Light-Matter Coupling as a Resource for Noiseless Quantum Memory

Inhomogeneous ensembles of two-level systems are important for both fundamental light-matter physics and quantum-network applications. Here we develop a general waveguide model that provides an intuitive and analytical description of collective dynamics in such systems by mapping the subradiant modes to an effective waveguide with well-defined input-output relations. For echo-based quantum memories, the model reveals the physical origin of noisy-echo suppression by adiabatic pulses and shows that inhomogeneous light-matter coupling can be harnessed as a resource for noiseless storage. For entanglement generation, the same mechanism exposes a previously unexplored limitation of robust control pulses and leads to a new composite-pulse protocol that overcomes it. These results establish the waveguide model as a practical bridge between fundamental collective physics and quantum-network protocol design, with direct implications for high-fidelity memories and robust entanglement generation in inhomogeneous ensembles.