Qiskit Pulse: Programming Quantum Computers Through the Cloud with
  Pulses
The quantum circuit model is an abstraction that hides the underlying
physical implementation of gates and measurements on a quantum computer. For
precise control of real quantum hardware, the ability to execute pulse and
readout-level instructions is required. To that end, we introduce Qiskit Pulse,
a pulse-level programming paradigm implemented as a module within Qiskit-Terra
\cite{Qiskit}. To demonstrate the capabilities of Qiskit Pulse, we calibrate
both un-echoed and echoed variants of the cross-resonance entangling gate with
a pair of qubits on an IBM Quantum system accessible through the cloud. We
perform Hamiltonian characterization of both single and two-pulse variants of
the cross-resonance entangling gate with varying amplitudes on a cloud-based
IBM Quantum system. We then transform these calibrated sequences into a
high-fidelity CNOT gate by applying pre and post local-rotations to the qubits,
achieving average gate fidelities of $F=0.981$ and $F=0.979$ for the un-echoed
and echoed respectively. This is comparable to the standard backend CNOT
fidelity of $F_{CX}=0.984$. Furthermore, to illustrate how users can access
their results at different levels of the readout chain, we build a custom
discriminator to investigate qubit readout correlations. Qiskit Pulse allows
users to explore advanced control schemes such as optimal control theory,
dynamical decoupling, and error mitigation that are not available within the
circuit model.
Thomas Alexander Naoki Kanazawa Daniel J. Egger Lauren Capelluto Christopher J. Wood Ali Javadi-Abhari David McKay