  Instruction scheduling is a key compiler optimization in quantum computing,
just as it is for classical computing. Current schedulers optimize for data
parallelism by allowing simultaneous execution of instructions, as long as
their qubits do not overlap. However, on many quantum hardware platforms,
instructions on overlapping qubits can be executed simultaneously through
__global interactions__. For example, while fan-out in traditional quantum
circuits can only be implemented sequentially when viewed at the logical level,
global interactions at the physical level allow fan-out to be achieved in one
step. We leverage this simultaneous fan-out primitive to optimize circuit
synthesis for NISQ (Noisy Intermediate-Scale Quantum) workloads. In addition,
we introduce novel quantum memory architectures based on fan-out.
  Our work also addresses hardware implementation of the fan-out primitive. We
perform realistic simulations for trapped ion quantum computers. We also
demonstrate experimental proof-of-concept of fan-out with superconducting
qubits. We perform depth (runtime) and fidelity estimation for NISQ application
circuits and quantum memory architectures under realistic noise models. Our
simulations indicate promising results with an asymptotic advantage in runtime,
as well as 7--24% reduction in error.
