Robust entangled state transmission and preparation in a trimer-like chain

We propose a scheme to achieve entangled state transmission and preparation via the topologically protected gap states in a trimer-like chain. By employing the trimer chain with tunable coupling strength, the transmission channel depending on the peculiar distribution of the gap states can be constructed, which allows for an entangled state transmission from the leftmost end to the rightmost end. We emphasize that the gap states are protected by the energy gap and, hence, are naturally immune to the mild disorder of coupling strength and on-site potential. Moreover, the chain manifests good scalability and can be extended to a local nonreciprocal coupling configuration. Combining the comprehensive influence of the gap state distribution characteristics and the local nonreciprocal coupling modulation, we implement a reliable entangled state preparation through the dynamical evolution of the gap states, in which the entangled state possesses an arbitrary entanglement form. Our work provides a method for investigating the transmission and preparation of entangled states within an extended Su–Schrieffer–Heeger model and is valuable for future quantum technologies relying on entanglement resources.