Time-optimal transfer of the quantum state in long qubit arrays

Recent technological advances have allowed the fabrication of large arrays of coherently operating coupled qubits, serving as prototypes for quantum processors. However, the optimal control of such systems is notoriously challenging because of the extremely large number of degrees of freedom. The lack of such control limits the potential of large-scale quantum systems.
In this talk, I will discuss a model problem of quantum state transfer in a large nearest-neighbor-coupled qubit array. I will present the optimal control strategy that simultaneously achieves maximal fidelity and minimal transfer time, reaching the quantum speed limit in a lattice with time-varying couplings.
Related paper:
https://arxiv.org/abs/2501.11933, accepted to Physical Review Letters