  Scalable architectures for quantum information technologies require to
selectively couple long-distance qubits while suppressing environmental noise
and cross-talk. In semiconductor materials, the coherent coupling of a single
spin on a quantum dot to a cavity hosting fermionic modes offers a new solution
to this technological challenge. Here, we demonstrate coherent coupling between
two spatially separated quantum dots using an electronic cavity design that
takes advantage of whispering-gallery modes in a two-dimensional electron gas.
The cavity-mediated long-distance coupling effectively minimizes undesirable
direct cross-talk between the dots and defines a scalable architecture for
all-electronic semiconductor-based quantum information processing.
