Tradeoffs in hybrid quantum-classical algorithms for designing quantum optimal controls

Quantum control holds promise for impacting fundamental research in physics, chemistry, and materials science. A persistent challenge in this field stems from the prohibitive cost of simulations, which are needed to inform quantum control advances in the laboratory. In this talk, we explore the costs and tradeoffs of performing quantum optimal control simulations based on the GRAPE and CRAB algorithms, when these algorithms are formulated as hybrid quantum-classical algorithms. In this setting, a quantum computer is responsible for performing the quantum dynamics simulations needed to evaluate the control objective functional, and potentially gradients thereof, via time-dependent Hamiltonian simulation. We will outline costs and tradeoffs associated with time-dependent Hamiltonian simulation using Trotter and post-Trotter methods, and contextualize this discussion with recent results obtained empirically through numerical simulation.

SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.