  The noisy and lengthy nature of quantum communication hinders the development
of distributed quantum computing. The inefficient design of existing compilers
for distributed quantum computing worsens the situation. Previous compilation
frameworks couple communication hardware with the implementation of expensive
remote gates. However, we discover that the efficiency of quantum
communication, especially collective communication, can be significantly
boosted by decoupling communication resources from remote operations, that is,
the communication hardware would be used only for preparing remote
entanglement, and the computational hardware, the component used to store
program information, would be used for conducting remote gates. Based on the
observation, we develop a compiler framework to optimize the collective
communication happening in distributed quantum programs. In this framework, we
decouple the communication preparation process in communication hardware from
the remote gates conducted in computational hardware by buffering EPR pairs
generated by communication hardware in qubits of the computational hardware.
Experimental results show that the proposed framework can halve the
communication cost of various distributed quantum programs, compared to
state-of-the-art compilers for distributed quantum computing.

Quantum Physics;Hardware Architecture