Real-time dissipation-engineering-assisted quantum state transfer near exceptional points

Dissipation engineering has provided an effective approach to realize non-Hermitian quantum systems. The complex energies of these systems are described by Riemann structures in the vicinity of non-Hermitian degeneracies—also known as exceptional points—and enable chiral quantum state transfer through dynamically tuning system parameters along a closed trajectory. While dissipation plays a critical role in this application, it also leads to unwanted decoherence for quantum states. Therefore, it is desirable to have full control of dissipation to minimize decoherence effect while maintaining state transfer. In this work, we implement cavity assisted bath engineering to a transmon superconducting circuit and realize real-time control of its dissipation rate. Through dynamically tuning the dissipation and other relevant parameters along a closed trajectory, we investigate quantum state transfer in a two-qubit device. This protocol is expected to transfer superposition states of single qubit and entangled states of two qubits with high fidelity. Our study opens new avenues to harness dissipation engineering and non-Hermitian physics in quantum technologies.