Enhanced entanglement via phase-controlled dark states in giant atom-waveguide QED
Phys. Rev. A 113, 023715 – Published 18 February, 2026
DOI: https://doi.org/10.1103/7dbx-mlfr
Abstract
In this paper, we investigate entanglement generation and optimization between two giant atoms coupled to a common one-dimensional waveguide. By introducing relative coupling phases between the connection points, we provide a unique approach to controlling quantum interference, which enables highly tunable decay dynamics of giant atoms into the waveguide. Within this framework, phase-dependent dark states can be precisely engineered to facilitate the spontaneous steady-state entanglement. For a single-excitation initial state, the maximum achievable entanglement exceeds the conventional upper bound of 0.5 for small atoms by . Moreover, the system maintains strong steady-state entanglement even under double-excitation conditions, which is not attainable with small atoms. Furthermore, by employing coherent two-atom driving, highly entangled steady states with concurrence can be achieved. The formation time is reduced by nearly two orders of magnitude compared to previous schemes, and no specific topology is required. Our results demonstrate the potential of giant atoms for quantum entanglement protocols and suggest promising applications in quantum information processing and large-scale quantum networks based on waveguide quantum electrodynamics.
