Error-Detectable Remote Entanglement between Dual-Rail Superconducting Cavity Modules: Part 2

As the sizes of quantum processors continue to increase, it becomes increasingly challenging to integrate all the constituent quantum modes into a monolithic device. One strategy to mitigate this issue is to design smaller-scale devices which are interconnected using coherent quantum communication links which can be used to perform inter-module operations, allowing the system to act as one large processor. Several protocols have been developed to successfully implement these links for superconducting qubits, but their fidelities are most often limited by losses associated with the link hardware. 

In this work, we propose a method to overcome this dominant source of infidelity by leveraging the erasure detection property of dual-rail cavity qubits. Local measurements in the modules can then convert photon loss events in the link into detectable errors. With this primary source of infidelity removed, we can achieve potentially higher fidelities for logical entangling gates across two remote modules.

In part two of this two-part talk, we demonstrate experimental implementation and operations on this system, including erasure qubit operation, erasure detection, and high-fidelity inter-module Bell state preparation.