  With the advent of public access to small gate-based quantum processors, it
becomes necessary to develop a benchmarking methodology such that independent
researchers can validate the operation of these processors. We explore the
usefulness of a number of simple quantum circuits as benchmarks for gate-based
quantum computing devices and show that circuits performing identity operations
are very simple, scalable and sensitive to gate errors and are therefore very
well suited for this task. We illustrate the procedure by presenting benchmark
results for the IBM Quantum Experience, a cloud-based platform for gate-based
quantum computing.
