Optimal control for Hamiltonian parameter estimation in non-commuting and bipartite quantum dynamics

Understand

The ability to characterise a Hamiltonian with high precision is crucial for the implementation of quantum technologies.

• In addition to the well-developed approaches utilising optimal probe states and optimal measurements, the method of optimal control can be used to identify time-dependent pulses applied to the system to achieve higher precision in the estimation of Hamiltonian parameters, especially in the presence of noise.
• Here, we extend optimally controlled estimation schemes for single qubits to non-commuting dynamics as well as two interacting qubits, demonstrating improvements in terms of maximal precision, time-stability, as well as robustness over uncontrolled protocols.