  Distributed quantum computing provides a viable approach towards scalable
quantum computation, which relies on nonlocal quantum gates to connect distant
quantum nodes, to overcome the limitation of a single device. However, such an
approach has only been realized within single nodes or between nodes separated
by a few tens of meters, preventing the target of harnessing computing
resources in large-scale quantum networks. Here, we demonstrate distributed
quantum computing between two nodes spatially separated by 7.0 km, using
stationary qubits based on multiplexed quantum memories, flying qubits at
telecom wavelengths, and active feedforward control based on field-deployed
fiber. Specifically, we illustrate quantum parallelism by implementing
Deutsch-Jozsa algorithm and quantum phase estimation algorithm between the two
remote nodes. These results represent the first demonstration of distributed
quantum computing over metropolitan-scale distances and lay the foundation for
the construction of large-scale quantum computing networks relying on existing
fiber channels.
