Controlling transfer and chirality of topological quantum state through dissipation in quantum walk

Dissipation always exists in real environments, and it can cause decoherence during transfer of quantum states. To avoid decoherence, dissipation is usually shielded. However, dissipation is difficult to avoid in real cases. Thus, how to achieve efficient quantum state transfer in dissipation environments, although it will receive great attention, remains a challenge. Here we demonstrate that dissipation can be utilized to realize robust control of quantum state transfer instead of being avoided. Our scheme is realized by constructing Liouvillian exceptional point (LEP). By tuning dissipation, the exchange of eigenvectors and nonadiabatic transition near the LEP can be modulated, thereby controlling transfer and chirality of topological quantum state. Furthermore, we have experimentally validated such a scheme on a quantum walk platform. Our work opens up a different avenue for quantum information process in real systems.