Universal gate sets provide a finite length of gate sequence that approximates any quantum operation with a given precision (Solovay-Kitaev theorem). Consequently, circuit composers can calibrate a finite set of single- and two-qubit gates, called "basis gates", and build their algorithm expressed with a sequence of the basis gates. While such essential calibrations are performed in backends on a regular basis, Qiskit users can also constract "customized gates" by scheduling user-defined drive waveforms to each qubit. By using Qiskit Pulse, we can develop customized gates and include them in our basis gates to boost the circuit. Furthermore, Qiskit Experiments provide the standard procedures to characterize, calibrate, and benchmark customized gates.
In a joint research with IBM, we are now performing such middleware development to expand the capabilities of quantum processors, for example by making special two-qubit gates and methods to benchmark them. We are also making these gates available to other users to feedback our outcomes and experiences to the community.