Fast and robust quantum state transfer assisted by zero-energy interface states in a splicing Su-Schrieffer-Heeger chain

Abstract

We propose a fast, robust, and long-distance quantum state transfer (QST) protocol via a splicing Su-Schrieffer-Heeger (SSH) chain, where the interchain couplings vary with the change in the phase parameter and the single or splicing SSH chain can be designed by adjusting it. It is found that the existence of a zero-energy interface state (IFS) not only can improve the speed of QST but also can realize long-distance QST. Furthermore, we give the phase diagram in the parameter space of the transfer time $T$ and the system's size $N$, where the different regions that can successfully implement QST via a single- or splicing-SSH-chain protocol are given. Therefore, we can choose the optimal QST protocol by adjusting only the phase parameter for different transfer times and system sizes. By numerically investigating the resilience of each protocol to static disorder, we reveal that the splicing-SSH-chain protocol is quite robust to both diagonal and off-diagonal disorders and clearly outperforms the single-SSH-chain protocol. By considering the environmental influence, rendering the Hamiltonian non-Hermitian by allowing energy to radiate away, our work shows that the QST protocol assisted by zero-energy IFS is more robust than previously expected and also outperforms the single-SSH-chain protocol.