Local control theory for superconducting qubits

In this work, we develop a method to design control pulses for fixed-frequency superconducting qubits coupled via tunable couplers based on local control theory, an approach commonly employed to steer chemical reactions. Local control theory provides an algorithm that only requires a single forward time propagation of the system wave function to shape an external pulse that monotonically increases the population of a desired final state of a quantum system given an initial state. The method can serve as a starting point for additional refinements that lead to new pulses with improved properties. Among others, we propose an algorithm to design pulses that transfer population in a reversible manner between given initial and final states of coupled fixed-frequency superconducting qubits.