Transmission and transformation of entangled states with high fidelity in a non-Hermitian system

The study of non-Hermitian systems has attracted more and more attention, because physical properties in many real systems should be described by non-Hermitian Hamiltonians. Due to the existence of absorption and dissipation, transmission and transformation of entangled states with high fidelity are very difficult to realize in the non-Hermitian systems. How to realize transmission and transformation of entangled states with high fidelity in these dissipative systems becomes an open problem. Here we provide an inverse design scheme for topologically protected channels to solve such a problem. From our scheme, topologically protected channels can be designed according to the requirements for the overlap integrals among the initial states, target states, and eigenstates of the system. As a result, robust transmission and transformation of entangled states with high fidelity can be achieved in the non-Hermitian systems. Our proposed scheme has been demonstrated experimentally using the constructed non-Hermitian quantum walk platform. This work interconnects topology, quantum physics, and non-Hermitian systems, and opens up an avenue for quantum engineering in real systems.