Minimizing state preparation times in pulse-level variational molecular simulations

Understand

Quantum simulation on NISQ devices is severely limited by short coherence times.

• A variational pulse-shaping algorithm known as ctrl-VQE was recently proposed to address this issue by eliminating the need for parameterized quantum circuits, which lead to long state preparation times.
• Here, we find the shortest possible pulses for ctrl-VQE to prepare target molecular wavefunctions for a given device Hamiltonian describing coupled transmon qubits.
• We find that the time-optimal pulses that do this have a bang-bang form consistent with Pontryagin's maximum principle.