  Significant advances have been made towards fault-tolerant operation of
silicon spin qubits, with single qubit fidelities exceeding 99.9%, several
demonstrations of two-qubit gates based on exchange coupling, and the
achievement of coherent single spin-photon coupling. Coupling arbitrary pairs
of spatially separated qubits in a quantum register poses a significant
challenge as most qubit systems are constrained to two dimensions (2D) with
nearest neighbor connectivity. For spins in silicon, new methods for quantum
state transfer should be developed to achieve connectivity beyond
nearest-neighbor exchange. Here we demonstrate shuttling of a single electron
across a linear array of 9 series-coupled Si quantum dots in ~50 ns via a
series of pairwise interdot charge transfers. By progressively constructing
more complex pulse sequences we perform parallel shuttling of 2 and 3 electrons
at a time through the 9-dot array. These experiments establish that physical
transport of single electrons is feasible in large silicon quantum dot arrays.
