Controlling Collective Quasiparticle Dynamics Beyond Decoherence in Topological Interfaces

Long-lived coherent quasiparticles are a promising foundation for novel quantum technologies, where maintaining quantum coherence is crucial. Decoherence, driven by finite emitter lifetimes, remains a central challenge in quantum computing. Here, we control the dynamics of spatially separated quantum emitters via preserving their phase information by introducing a topological waveguide as a robust chiral reservoir. Incoherent quantum emitters randomly positioned near a perturbed honeycomb plasmonic interface and couple to the mutual topological interface mode. Using the S ₃ Stokes parameter, we trace far-field polarization patterns that reflect emitter coherence and spin–momentum locking. We show that even weakly coupled emitters exhibit coherent excitation and imprint phase on the emission. Time-domain dynamics reveal signatures of superradiance and subradiance that correlate with spatial interference in S _3. These spatial-temporal features confirm that the observed polarization patterns arise from coherent quantum many-body dynamics, not classical interference. This challenges the conventional dichotomy between incoherent and coherent regimes, revealing that topological chiral photonic environments mediate long-range quantum correlations beyond standard waveguide QED.