Tunable quantum router with giant atoms, implementing quantum gates, teleportation, non-reciprocity, and circulators

Abstract: The unique photon-scattering phenomena of giant-atom systems offer a novel paradigm for exploring innovative quantum optics phenomena and applications. Here, we investigate a giant-atom configuration embedded in a dual-rail waveguide, whose scattering behavior is analytically derived based on a four-port model and affected by both waveguide-induced and interatomic interaction phases. One can modulate these phases to achieve targeted routing and non-reciprocal scattering of photons. Furthermore, using such a configuration, we propose quantum applications such as quantum storage, path-encoded quantum gates (e.g., CNOT gate), quantum teleportation, and quantum circulators. This configuration can be implemented with state-of-the-art solid-state quantum systems, enabling a wide range of quantum applications and facilitating the development of quantum networks.